Add a NavigationThrottle to the public content/ interface

This CL adds a NavigationThrottle class to the public content/ interface. A NavigationThrottle is used to control the flow of navigations. It lives entirely on the UI thread. Eventually, all components that want the functionality of a ResourceThrottle for navigations should transition to a NavigationThrottle: the new architecture for navigations (browser-side navigation) will not support ResourceThrottles for main resources load. See https://docs.google.com/document/d/1ICLLQoC9EsZ-bWH4ZKRhPCIoZKn6pOj02SlGl6SKH6Y/edit?pli=1#heading=h.fmxjmgvbgg7x for the design doc.

This Cl also transition the InterceptNavigationresourceThrottle to the Navigationthrottle model.
BUG=504347

Review URL: https://codereview.chromium.org/1269813002

Cr-Commit-Position: refs/heads/master@{#350092}

36 files changed, 1025 insertions, 820 deletions

diff --git a/android_webview/browser/aw_content_browser_client.cc b/android_webview/browser/aw_content_browser_client.cc
index 759c844..ab14d49 100644
--- a/android_webview/browser/aw_content_browser_client.cc
+++ b/android_webview/browser/aw_content_browser_client.cc
@@ -25,10 +25,13 @@
 #include "base/command_line.h"
 #include "base/path_service.h"
 #include "components/cdm/browser/cdm_message_filter_android.h"
+#include "components/navigation_interception/intercept_navigation_delegate.h"
 #include "content/public/browser/access_token_store.h"
 #include "content/public/browser/browser_message_filter.h"
 #include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/client_certificate_delegate.h"
+#include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
@@ -487,6 +490,22 @@ void AwContentBrowserClient::OverrideWebkitPrefs(
       content::WebContents::FromRenderViewHost(rvh), web_prefs);
 }
 
+ScopedVector<content::NavigationThrottle>
+AwContentBrowserClient::CreateThrottlesForNavigation(
+    content::NavigationHandle* navigation_handle) {
+  ScopedVector<content::NavigationThrottle> throttles;
+  if (navigation_handle->IsInMainFrame() ||
+      (!navigation_handle->GetURL().SchemeIs(url::kHttpScheme) &&
+       !navigation_handle->GetURL().SchemeIs(url::kHttpsScheme) &&
+       !navigation_handle->GetURL().SchemeIs(url::kAboutScheme))) {
+    throttles.push_back(
+        navigation_interception::InterceptNavigationDelegate::CreateThrottleFor(
+            navigation_handle)
+            .Pass());
+  }
+  return throttles.Pass();
+}
+
 #if defined(VIDEO_HOLE)
 content::ExternalVideoSurfaceContainer*
 AwContentBrowserClient::OverrideCreateExternalVideoSurfaceContainer(
diff --git a/android_webview/browser/aw_content_browser_client.h b/android_webview/browser/aw_content_browser_client.h
index d811cf2..a3a814e 100644
--- a/android_webview/browser/aw_content_browser_client.h
+++ b/android_webview/browser/aw_content_browser_client.h
@@ -142,6 +142,8 @@ class AwContentBrowserClient : public content::ContentBrowserClient {
       std::map<int, base::MemoryMappedFile::Region>* regions) override;
   void OverrideWebkitPrefs(content::RenderViewHost* rvh,
                            content::WebPreferences* web_prefs) override;
+  ScopedVector<content::NavigationThrottle> CreateThrottlesForNavigation(
+      content::NavigationHandle* navigation_handle) override;
 #if defined(VIDEO_HOLE)
   content::ExternalVideoSurfaceContainer*
   OverrideCreateExternalVideoSurfaceContainer(
diff --git a/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc b/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
index 1d9e585..ed7c52b 100644
--- a/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
+++ b/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
@@ -221,14 +221,6 @@ void AwResourceDispatcherHostDelegate::RequestBeginning(
   throttles->push_back(new IoThreadClientThrottle(
       request_info->GetChildID(), request_info->GetRenderFrameID(), request));
 
-  if (resource_type == content::RESOURCE_TYPE_MAIN_FRAME ||
-      (resource_type == content::RESOURCE_TYPE_SUB_FRAME &&
-       !request->url().SchemeIs(url::kHttpScheme) &&
-       !request->url().SchemeIs(url::kHttpsScheme) &&
-       !request->url().SchemeIs(url::kAboutScheme))) {
-    throttles->push_back(InterceptNavigationDelegate::CreateThrottleFor(
-        request));
-  }
   if (resource_type != content::RESOURCE_TYPE_MAIN_FRAME)
     InterceptNavigationDelegate::UpdateUserGestureCarryoverInfo(request);
 }
diff --git a/chrome/browser/apps/app_url_redirector.cc b/chrome/browser/apps/app_url_redirector.cc
index cf15169..6396293 100644
--- a/chrome/browser/apps/app_url_redirector.cc
+++ b/chrome/browser/apps/app_url_redirector.cc
@@ -9,22 +9,18 @@
 #include "base/logging.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/common/extensions/api/url_handlers/url_handlers_parser.h"
-#include "components/navigation_interception/intercept_navigation_resource_throttle.h"
+#include "components/navigation_interception/intercept_navigation_throttle.h"
 #include "components/navigation_interception/navigation_params.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/resource_request_info.h"
-#include "content/public/browser/resource_throttle.h"
+#include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/web_contents.h"
-#include "extensions/browser/info_map.h"
+#include "extensions/browser/extension_registry.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/extension_set.h"
 #include "net/url_request/url_request.h"
 
 using content::BrowserThread;
-using content::ResourceRequestInfo;
 using content::WebContents;
 using extensions::Extension;
 using extensions::UrlHandlers;
@@ -55,8 +51,8 @@ bool LaunchAppWithUrl(
   }
 
   // These are guaranteed by CreateThrottleFor below.
-  DCHECK(!params.is_post());
   DCHECK(UrlHandlers::CanExtensionHandleUrl(app.get(), params.url()));
+  DCHECK(!params.is_post());
 
   Profile* profile =
       Profile::FromBrowserContext(source->GetBrowserContext());
@@ -73,57 +69,54 @@ bool LaunchAppWithUrl(
 }  // namespace
 
 // static
-content::ResourceThrottle*
-AppUrlRedirector::MaybeCreateThrottleFor(net::URLRequest* request,
-                                         ProfileIOData* profile_io_data) {
-  DVLOG(1) << "Considering URL for redirection: "
-           << request->method() << " " << request->url().spec();
+scoped_ptr<content::NavigationThrottle>
+AppUrlRedirector::MaybeCreateThrottleFor(content::NavigationHandle* handle) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DVLOG(1) << "Considering URL for redirection: " << handle->GetURL().spec();
+
+  content::BrowserContext* browser_context =
+      handle->GetWebContents()->GetBrowserContext();
+  DCHECK(browser_context);
 
   // Support only GET for now.
-  if (request->method() != "GET") {
+  if (handle->IsPost()) {
     DVLOG(1) << "Skip redirection: method is not GET";
-    return NULL;
+    return nullptr;
   }
 
-  if (!request->url().SchemeIsHTTPOrHTTPS()) {
+  if (!handle->GetURL().SchemeIsHTTPOrHTTPS()) {
     DVLOG(1) << "Skip redirection: scheme is not HTTP or HTTPS";
-    return NULL;
-  }
-
-  // The user has indicated that a URL should be force downloaded. Turn off
-  // URL redirection in this case.
-  if (ResourceRequestInfo::ForRequest(request)->IsDownload()) {
-    DVLOG(1) << "Skip redirection: request is a forced download";
-    return NULL;
+    return nullptr;
   }
 
   // Never redirect URLs to apps in incognito. Technically, apps are not
   // supported in incognito, but that may change in future.
   // See crbug.com/240879, which tracks incognito support for v2 apps.
-  if (profile_io_data->IsOffTheRecord()) {
+  Profile* profile = Profile::FromBrowserContext(browser_context);
+  if (profile->GetProfileType() == Profile::INCOGNITO_PROFILE) {
     DVLOG(1) << "Skip redirection: unsupported in incognito";
-    return NULL;
+    return nullptr;
   }
 
-  const extensions::ExtensionSet& extensions =
-      profile_io_data->GetExtensionInfoMap()->extensions();
-  for (extensions::ExtensionSet::const_iterator iter = extensions.begin();
-       iter != extensions.end();
-       ++iter) {
+  const extensions::ExtensionSet& enabled_extensions =
+      extensions::ExtensionRegistry::Get(browser_context)->enabled_extensions();
+  for (extensions::ExtensionSet::const_iterator iter =
+           enabled_extensions.begin();
+       iter != enabled_extensions.end(); ++iter) {
     const UrlHandlerInfo* handler =
-        UrlHandlers::FindMatchingUrlHandler(iter->get(), request->url());
+        UrlHandlers::FindMatchingUrlHandler(iter->get(), handle->GetURL());
     if (handler) {
       DVLOG(1) << "Found matching app handler for redirection: "
                << (*iter)->name() << "(" << (*iter)->id() << "):"
                << handler->id;
-      return new navigation_interception::InterceptNavigationResourceThrottle(
-          request,
-          base::Bind(&LaunchAppWithUrl,
-                     scoped_refptr<const Extension>(*iter),
-                     handler->id));
+      return scoped_ptr<content::NavigationThrottle>(
+          new navigation_interception::InterceptNavigationThrottle(
+              handle,
+              base::Bind(&LaunchAppWithUrl,
+                         scoped_refptr<const Extension>(*iter), handler->id)));
     }
   }
 
   DVLOG(1) << "Skipping redirection: no matching app handler found";
-  return NULL;
+  return nullptr;
 }
diff --git a/chrome/browser/apps/app_url_redirector.h b/chrome/browser/apps/app_url_redirector.h
index 331d7b4..629af37 100644
--- a/chrome/browser/apps/app_url_redirector.h
+++ b/chrome/browser/apps/app_url_redirector.h
@@ -6,24 +6,22 @@
 #define CHROME_BROWSER_APPS_APP_URL_REDIRECTOR_H_
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/public/browser/navigation_throttle.h"
 
 namespace content {
-class ResourceThrottle;
+class NavigationHandle;
+class NavigationThrottle;
+class WebContents;
 }
 
-namespace net {
-class URLRequest;
-}
-
-class ProfileIOData;
-
-// This class creates resource throttles that redirect URLs to apps that
-// have a matching URL handler in the 'url_handlers' manifest key.
+// This class creates navigation throttles that redirect URLs to apps that have
+// a matching URL handler in the 'url_handlers' manifest key. Note that this is
+// a UI thread class.
 class AppUrlRedirector {
  public:
-  static content::ResourceThrottle* MaybeCreateThrottleFor(
-      net::URLRequest* request,
-      ProfileIOData* profile_io_data);
+  static scoped_ptr<content::NavigationThrottle> MaybeCreateThrottleFor(
+      content::NavigationHandle* handle);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AppUrlRedirector);
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 25f4aa4..bbe1c07 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -24,6 +24,7 @@
 #include "base/thread_task_runner_handle.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/after_startup_task_utils.h"
+#include "chrome/browser/apps/app_url_redirector.h"
 #include "chrome/browser/browser_about_handler.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_shutdown.h"
@@ -120,6 +121,8 @@
 #include "content/public/browser/child_process_data.h"
 #include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/client_certificate_delegate.h"
+#include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
@@ -173,6 +176,7 @@
 #include "chrome/browser/chrome_browser_main_android.h"
 #include "chrome/common/descriptors_android.h"
 #include "components/crash/content/browser/crash_dump_manager_android.h"
+#include "components/navigation_interception/intercept_navigation_delegate.h"
 #include "components/service_tab_launcher/browser/android/service_tab_launcher.h"
 #include "ui/base/resource/resource_bundle_android.h"
 #elif defined(OS_POSIX)
@@ -2598,6 +2602,34 @@ void ChromeContentBrowserClient::RecordURLMetric(const std::string& metric,
   }
 }
 
+ScopedVector<content::NavigationThrottle>
+ChromeContentBrowserClient::CreateThrottlesForNavigation(
+    content::NavigationHandle* handle) {
+  ScopedVector<content::NavigationThrottle> throttles;
+#if defined(OS_ANDROID)
+  // TODO(davidben): This is insufficient to integrate with prerender properly.
+  // https://crbug.com/370595
+  prerender::PrerenderContents* prerender_contents =
+      prerender::PrerenderContents::FromWebContents(handle->GetWebContents());
+  if (!prerender_contents && handle->IsInMainFrame()) {
+    throttles.push_back(
+        navigation_interception::InterceptNavigationDelegate::CreateThrottleFor(
+            handle)
+            .Pass());
+  }
+#else
+  if (handle->IsInMainFrame()) {
+    // Redirect some navigations to apps that have registered matching URL
+    // handlers ('url_handlers' in the manifest).
+    scoped_ptr<content::NavigationThrottle> url_to_app_throttle =
+        AppUrlRedirector::MaybeCreateThrottleFor(handle);
+    if (url_to_app_throttle)
+      throttles.push_back(url_to_app_throttle.Pass());
+  }
+#endif
+  return throttles.Pass();
+}
+
 content::DevToolsManagerDelegate*
 ChromeContentBrowserClient::GetDevToolsManagerDelegate() {
   return new ChromeDevToolsManagerDelegate();
diff --git a/chrome/browser/chrome_content_browser_client.h b/chrome/browser/chrome_content_browser_client.h
index a8b6270..1e2e97f 100644
--- a/chrome/browser/chrome_content_browser_client.h
+++ b/chrome/browser/chrome_content_browser_client.h
@@ -285,6 +285,8 @@ class ChromeContentBrowserClient : public content::ContentBrowserClient {
       content::WebContents* web_contents) override;
 
   void RecordURLMetric(const std::string& metric, const GURL& url) override;
+  ScopedVector<content::NavigationThrottle> CreateThrottlesForNavigation(
+      content::NavigationHandle* handle) override;
 
  private:
   friend class DisableWebRtcEncryptionFlagTest;
diff --git a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
index aa4705e..b28332e 100644
--- a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
+++ b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
@@ -339,25 +339,8 @@ void ChromeResourceDispatcherHostDelegate::RequestBeginning(
       resource_context);
 
 #if defined(OS_ANDROID)
-  // TODO(davidben): This is insufficient to integrate with prerender properly.
-  // https://crbug.com/370595
-  if (!is_prerendering) {
-    if (resource_type == content::RESOURCE_TYPE_MAIN_FRAME) {
-      throttles->push_back(
-          InterceptNavigationDelegate::CreateThrottleFor(request));
-    } else {
-      InterceptNavigationDelegate::UpdateUserGestureCarryoverInfo(request);
-    }
-  }
-#else
-  if (resource_type == content::RESOURCE_TYPE_MAIN_FRAME) {
-    // Redirect some navigations to apps that have registered matching URL
-    // handlers ('url_handlers' in the manifest).
-    content::ResourceThrottle* url_to_app_throttle =
-        AppUrlRedirector::MaybeCreateThrottleFor(request, io_data);
-    if (url_to_app_throttle)
-      throttles->push_back(url_to_app_throttle);
-  }
+  if (resource_type != content::RESOURCE_TYPE_MAIN_FRAME)
+    InterceptNavigationDelegate::UpdateUserGestureCarryoverInfo(request);
 #endif
 
 #if defined(OS_CHROMEOS)
diff --git a/components/components_tests.gyp b/components/components_tests.gyp
index 8e3d46c..78a981d 100644
--- a/components/components_tests.gyp
+++ b/components/components_tests.gyp
@@ -353,7 +353,7 @@
       'nacl/zygote/nacl_fork_delegate_linux_unittest.cc',
     ],
     'navigation_interception_unittest_sources': [
-      'navigation_interception/intercept_navigation_resource_throttle_unittest.cc',
+      'navigation_interception/intercept_navigation_throttle_unittest.cc',
     ],
     'network_hints_unittest_sources': [
       'network_hints/renderer/dns_prefetch_queue_unittest.cc',
diff --git a/components/navigation_interception.gypi b/components/navigation_interception.gypi
index 3511201..7ccc4cd 100644
--- a/components/navigation_interception.gypi
+++ b/components/navigation_interception.gypi
@@ -23,8 +23,8 @@
       ],
       'sources': [
         # Note: sources list duplicated in GN build.
-        'navigation_interception/intercept_navigation_resource_throttle.cc',
-        'navigation_interception/intercept_navigation_resource_throttle.h',
+        'navigation_interception/intercept_navigation_throttle.cc',
+        'navigation_interception/intercept_navigation_throttle.h',
         'navigation_interception/navigation_params.cc',
         'navigation_interception/navigation_params.h',
       ],
diff --git a/components/navigation_interception/BUILD.gn b/components/navigation_interception/BUILD.gn
index 12456ff..f268510 100644
--- a/components/navigation_interception/BUILD.gn
+++ b/components/navigation_interception/BUILD.gn
@@ -8,8 +8,8 @@ if (is_android) {
 
 source_set("navigation_interception") {
   sources = [
-    "intercept_navigation_resource_throttle.cc",
-    "intercept_navigation_resource_throttle.h",
+    "intercept_navigation_throttle.cc",
+    "intercept_navigation_throttle.h",
     "navigation_params.cc",
     "navigation_params.h",
   ]
@@ -49,7 +49,7 @@ if (is_android) {
 source_set("unit_tests") {
   testonly = true
   sources = [
-    "intercept_navigation_resource_throttle_unittest.cc",
+    "intercept_navigation_throttle_unittest.cc",
   ]
   deps = [
     ":navigation_interception",
diff --git a/components/navigation_interception/intercept_navigation_delegate.cc b/components/navigation_interception/intercept_navigation_delegate.cc
index ba9053d..11017f3b 100644
--- a/components/navigation_interception/intercept_navigation_delegate.cc
+++ b/components/navigation_interception/intercept_navigation_delegate.cc
@@ -7,9 +7,10 @@
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/callback.h"
-#include "components/navigation_interception/intercept_navigation_resource_throttle.h"
+#include "components/navigation_interception/intercept_navigation_throttle.h"
 #include "components/navigation_interception/navigation_params_android.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_request_info.h"
@@ -83,10 +84,12 @@ InterceptNavigationDelegate* InterceptNavigationDelegate::Get(
 }
 
 // static
-content::ResourceThrottle* InterceptNavigationDelegate::CreateThrottleFor(
-    net::URLRequest* request) {
-  return new InterceptNavigationResourceThrottle(
-      request, base::Bind(&CheckIfShouldIgnoreNavigationOnUIThread));
+scoped_ptr<content::NavigationThrottle>
+InterceptNavigationDelegate::CreateThrottleFor(
+    content::NavigationHandle* handle) {
+  return scoped_ptr<content::NavigationThrottle>(
+      new InterceptNavigationThrottle(
+          handle, base::Bind(&CheckIfShouldIgnoreNavigationOnUIThread)));
 }
 
 // static
diff --git a/components/navigation_interception/intercept_navigation_delegate.h b/components/navigation_interception/intercept_navigation_delegate.h
index d84969f..57858fd 100644
--- a/components/navigation_interception/intercept_navigation_delegate.h
+++ b/components/navigation_interception/intercept_navigation_delegate.h
@@ -12,7 +12,8 @@
 class GURL;
 
 namespace content {
-class ResourceThrottle;
+class NavigationHandle;
+class NavigationThrottle;
 class WebContents;
 }
 
@@ -32,9 +33,8 @@ class NavigationParams;
 // 1) the Java-side interface implementation must be associated (via the
 //    Associate method) with a WebContents for which URLRequests are to be
 //    intercepted,
-// 2) the ResourceThrottle obtained via CreateThrottleFor must be associated
-//    with the URLRequests in the ResourceDispatcherHostDelegate
-//    implementation.
+// 2) the NavigationThrottle obtained via CreateThrottleFor must be associated
+//    with the NavigationHandle in the ContentBrowserClient implementation.
 class InterceptNavigationDelegate : public base::SupportsUserData::Data {
  public:
   InterceptNavigationDelegate(JNIEnv* env, jobject jdelegate);
@@ -50,10 +50,10 @@ class InterceptNavigationDelegate : public base::SupportsUserData::Data {
   // can be null.
   static InterceptNavigationDelegate* Get(content::WebContents* web_contents);
 
-  // Creates a InterceptNavigationResourceThrottle that will direct all
-  // callbacks to the InterceptNavigationDelegate.
-  static content::ResourceThrottle* CreateThrottleFor(
-      net::URLRequest* request);
+  // Creates a InterceptNavigationThrottle that will direct all callbacks to
+  // the InterceptNavigationDelegate.
+  static scoped_ptr<content::NavigationThrottle> CreateThrottleFor(
+      content::NavigationHandle* handle);
 
   // Updates information to determine whether to have user gesture carryover or
   // not.
diff --git a/components/navigation_interception/intercept_navigation_resource_throttle.cc b/components/navigation_interception/intercept_navigation_resource_throttle.cc
deleted file mode 100644
index 1b0b89f..0000000
--- a/components/navigation_interception/intercept_navigation_resource_throttle.cc
+++ /dev/null
@@ -1,146 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/navigation_interception/intercept_navigation_resource_throttle.h"
-
-#include "components/navigation_interception/navigation_params.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/child_process_security_policy.h"
-#include "content/public/browser/render_frame_host.h"
-#include "content/public/browser/render_process_host.h"
-#include "content/public/browser/resource_context.h"
-#include "content/public/browser/resource_controller.h"
-#include "content/public/browser/resource_request_info.h"
-#include "content/public/browser/web_contents.h"
-#include "content/public/common/referrer.h"
-#include "net/http/http_response_headers.h"
-#include "net/url_request/redirect_info.h"
-#include "net/url_request/url_request_context.h"
-#include "net/url_request/url_request_job_factory.h"
-#include "net/url_request/url_request.h"
-#include "ui/base/page_transition_types.h"
-
-using content::BrowserThread;
-using content::ChildProcessSecurityPolicy;
-using ui::PageTransition;
-using content::Referrer;
-using content::RenderProcessHost;
-using content::ResourceRequestInfo;
-
-namespace navigation_interception {
-
-namespace {
-
-void CheckIfShouldIgnoreNavigationOnUIThread(
-    int render_process_id,
-    int render_frame_id,
-    const NavigationParams& navigation_params,
-    InterceptNavigationResourceThrottle::CheckOnUIThreadCallback
-    should_ignore_callback,
-    base::Callback<void(bool)> callback) {
-  bool should_ignore_navigation = false;
-  RenderProcessHost* rph = RenderProcessHost::FromID(render_process_id);
-  if (rph) {
-    NavigationParams validated_params(navigation_params);
-    rph->FilterURL(false, &validated_params.url());
-
-    content::RenderFrameHost* render_frame_host =
-        content::RenderFrameHost::FromID(render_process_id, render_frame_id);
-    content::WebContents* web_contents =
-        content::WebContents::FromRenderFrameHost(render_frame_host);
-
-    if (web_contents) {
-      should_ignore_navigation = should_ignore_callback.Run(web_contents,
-                                                            validated_params);
-    }
-  }
-
-  BrowserThread::PostTask(
-      BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(callback, should_ignore_navigation));
-}
-
-} // namespace
-
-InterceptNavigationResourceThrottle::InterceptNavigationResourceThrottle(
-    net::URLRequest* request,
-    CheckOnUIThreadCallback should_ignore_callback)
-    : request_(request),
-      should_ignore_callback_(should_ignore_callback),
-      weak_ptr_factory_(this) {
-}
-
-InterceptNavigationResourceThrottle::~InterceptNavigationResourceThrottle() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-}
-
-void InterceptNavigationResourceThrottle::WillStartRequest(bool* defer) {
-  *defer =
-      CheckIfShouldIgnoreNavigation(request_->url(), request_->method(), false);
-}
-
-void InterceptNavigationResourceThrottle::WillRedirectRequest(
-    const net::RedirectInfo& redirect_info,
-    bool* defer) {
-  *defer = CheckIfShouldIgnoreNavigation(redirect_info.new_url,
-                                         redirect_info.new_method, true);
-}
-
-const char* InterceptNavigationResourceThrottle::GetNameForLogging() const {
-  return "InterceptNavigationResourceThrottle";
-}
-
-bool InterceptNavigationResourceThrottle::CheckIfShouldIgnoreNavigation(
-    const GURL& url,
-    const std::string& method,
-    bool is_redirect) {
-  const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request_);
-  if (!info)
-    return false;
-
-  int render_process_id, render_frame_id;
-  if (!info->GetAssociatedRenderFrame(&render_process_id, &render_frame_id))
-    return false;
-
-  bool is_external_protocol =
-      !info->GetContext()->GetRequestContext()->job_factory()->IsHandledURL(
-          url);
-  NavigationParams navigation_params(
-      url,
-      Referrer::SanitizeForRequest(
-          url, Referrer(GURL(request_->referrer()), info->GetReferrerPolicy())),
-      info->HasUserGesture(), method == "POST", info->GetPageTransition(),
-      is_redirect, is_external_protocol, true);
-
-  BrowserThread::PostTask(
-      BrowserThread::UI,
-      FROM_HERE,
-      base::Bind(
-          &CheckIfShouldIgnoreNavigationOnUIThread,
-          render_process_id,
-          render_frame_id,
-          navigation_params,
-          should_ignore_callback_,
-          base::Bind(
-              &InterceptNavigationResourceThrottle::OnResultObtained,
-              weak_ptr_factory_.GetWeakPtr())));
-
-  // Defer request while we wait for the UI thread to check if the navigation
-  // should be ignored.
-  return true;
-}
-
-void InterceptNavigationResourceThrottle::OnResultObtained(
-    bool should_ignore_navigation) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-
-  if (should_ignore_navigation) {
-    controller()->CancelAndIgnore();
-  } else {
-    controller()->Resume();
-  }
-}
-
-}  // namespace navigation_interception
diff --git a/components/navigation_interception/intercept_navigation_resource_throttle.h b/components/navigation_interception/intercept_navigation_resource_throttle.h
deleted file mode 100644
index db3a714..0000000
--- a/components/navigation_interception/intercept_navigation_resource_throttle.h
+++ /dev/null
@@ -1,63 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_RESOURCE_THROTTLE_H_
-#define COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_RESOURCE_THROTTLE_H_
-
-#include <string>
-
-#include "base/callback.h"
-#include "base/memory/weak_ptr.h"
-#include "content/public/browser/resource_throttle.h"
-
-class GURL;
-
-namespace content {
-class WebContents;
-}
-
-namespace net {
-class URLRequest;
-}
-
-namespace navigation_interception {
-
-class NavigationParams;
-
-// This class allows the provider of the Callback to selectively ignore top
-// level navigations.
-class InterceptNavigationResourceThrottle : public content::ResourceThrottle {
- public:
-  typedef base::Callback<bool(
-          content::WebContents* /* source */,
-          const NavigationParams& /* navigation_params */)>
-      CheckOnUIThreadCallback;
-
-  InterceptNavigationResourceThrottle(
-      net::URLRequest* request,
-      CheckOnUIThreadCallback should_ignore_callback);
-  ~InterceptNavigationResourceThrottle() override;
-
-  // content::ResourceThrottle implementation:
-  void WillStartRequest(bool* defer) override;
-  void WillRedirectRequest(const net::RedirectInfo& redirect_info,
-                           bool* defer) override;
-  const char* GetNameForLogging() const override;
-
- private:
-  bool CheckIfShouldIgnoreNavigation(const GURL& url,
-                                     const std::string& method,
-                                     bool is_redirect);
-  void OnResultObtained(bool should_ignore_navigation);
-
-  net::URLRequest* request_;
-  CheckOnUIThreadCallback should_ignore_callback_;
-  base::WeakPtrFactory<InterceptNavigationResourceThrottle> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(InterceptNavigationResourceThrottle);
-};
-
-}  // namespace navigation_interception
-
-#endif  // COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_RESOURCE_THROTTLE_H_
diff --git a/components/navigation_interception/intercept_navigation_resource_throttle_unittest.cc b/components/navigation_interception/intercept_navigation_resource_throttle_unittest.cc
deleted file mode 100644
index 8855f42..0000000
--- a/components/navigation_interception/intercept_navigation_resource_throttle_unittest.cc
+++ /dev/null
@@ -1,481 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/run_loop.h"
-#include "base/synchronization/waitable_event.h"
-#include "components/navigation_interception/intercept_navigation_resource_throttle.h"
-#include "components/navigation_interception/navigation_params.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/render_frame_host.h"
-#include "content/public/browser/render_process_host.h"
-#include "content/public/browser/resource_context.h"
-#include "content/public/browser/resource_controller.h"
-#include "content/public/browser/resource_dispatcher_host.h"
-#include "content/public/browser/resource_dispatcher_host_delegate.h"
-#include "content/public/browser/resource_request_info.h"
-#include "content/public/browser/resource_throttle.h"
-#include "content/public/browser/web_contents.h"
-#include "content/public/browser/web_contents_delegate.h"
-#include "content/public/test/mock_resource_context.h"
-#include "content/public/test/test_renderer_host.h"
-#include "net/base/request_priority.h"
-#include "net/http/http_response_headers.h"
-#include "net/http/http_response_info.h"
-#include "net/url_request/redirect_info.h"
-#include "net/url_request/url_request.h"
-#include "net/url_request/url_request_test_util.h"
-#include "testing/gmock/include/gmock/gmock.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-using content::ResourceType;
-using testing::_;
-using testing::Eq;
-using testing::Ne;
-using testing::Property;
-using testing::Return;
-
-namespace navigation_interception {
-
-namespace {
-
-const char kTestUrl[] = "http://www.test.com/";
-const char kUnsafeTestUrl[] = "about:crash";
-
-// The MS C++ compiler complains about not being able to resolve which url()
-// method (const or non-const) to use if we use the Property matcher to check
-// the return value of the NavigationParams::url() method.
-// It is possible to suppress the error by specifying the types directly but
-// that results in very ugly syntax, which is why these custom matchers are
-// used instead.
-MATCHER(NavigationParamsUrlIsTest, "") {
-  return arg.url() == GURL(kTestUrl);
-}
-
-MATCHER(NavigationParamsUrlIsSafe, "") {
-  return arg.url() != GURL(kUnsafeTestUrl);
-}
-
-}  // namespace
-
-
-// MockInterceptCallbackReceiver ----------------------------------------------
-
-class MockInterceptCallbackReceiver {
- public:
-  MOCK_METHOD2(ShouldIgnoreNavigation,
-               bool(content::WebContents* source,
-                    const NavigationParams& navigation_params));
-};
-
-// MockResourceController -----------------------------------------------------
-class MockResourceController : public content::ResourceController {
- public:
-  enum Status {
-    UNKNOWN,
-    RESUMED,
-    CANCELLED
-  };
-
-  MockResourceController()
-      : status_(UNKNOWN) {
-  }
-
-  Status status() const { return status_; }
-
-  // ResourceController:
-  void Cancel() override { NOTREACHED(); }
-  void CancelAndIgnore() override { status_ = CANCELLED; }
-  void CancelWithError(int error_code) override { NOTREACHED(); }
-  void Resume() override {
-    DCHECK(status_ == UNKNOWN);
-    status_ = RESUMED;
-  }
-
- private:
-  Status status_;
-};
-
-// TestIOThreadState ----------------------------------------------------------
-
-enum RedirectMode {
-  REDIRECT_MODE_NO_REDIRECT,
-  REDIRECT_MODE_302,
-};
-
-class TestIOThreadState {
- public:
-  TestIOThreadState(const GURL& url,
-                    int render_process_id,
-                    int render_frame_id,
-                    const std::string& request_method,
-                    RedirectMode redirect_mode,
-                    MockInterceptCallbackReceiver* callback_receiver)
-      : resource_context_(&test_url_request_context_),
-        request_(resource_context_.GetRequestContext()->CreateRequest(
-                     url,
-                     net::DEFAULT_PRIORITY,
-                     NULL /* delegate */)) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-    if (render_process_id != MSG_ROUTING_NONE &&
-        render_frame_id != MSG_ROUTING_NONE) {
-      content::ResourceRequestInfo::AllocateForTesting(
-          request_.get(),
-          content::RESOURCE_TYPE_MAIN_FRAME,
-          &resource_context_,
-          render_process_id,
-          MSG_ROUTING_NONE,
-          render_frame_id,
-          true,    // is_main_frame
-          false,   // parent_is_main_frame
-          true,    // allow_download
-          false);  // is_async
-    }
-    throttle_.reset(new InterceptNavigationResourceThrottle(
-        request_.get(),
-        base::Bind(&MockInterceptCallbackReceiver::ShouldIgnoreNavigation,
-                   base::Unretained(callback_receiver))));
-    throttle_->set_controller_for_testing(&throttle_controller_);
-    request_->set_method(request_method);
-
-    if (redirect_mode == REDIRECT_MODE_302) {
-      net::HttpResponseInfo& response_info =
-          const_cast<net::HttpResponseInfo&>(request_->response_info());
-      response_info.headers = new net::HttpResponseHeaders(
-          "Status: 302 Found\0\0");
-    }
-  }
-
-  void ThrottleWillStartRequest(bool* defer) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-    throttle_->WillStartRequest(defer);
-  }
-
-  void ThrottleWillRedirectRequest(const net::RedirectInfo& redirect_info,
-                                   bool* defer) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-    throttle_->WillRedirectRequest(redirect_info, defer);
-  }
-
-  bool request_resumed() const {
-    return throttle_controller_.status() ==
-        MockResourceController::RESUMED;
-  }
-
-  bool request_cancelled() const {
-    return throttle_controller_.status() ==
-        MockResourceController::CANCELLED;
-  }
-
- private:
-  net::TestURLRequestContext test_url_request_context_;
-  content::MockResourceContext resource_context_;
-  scoped_ptr<net::URLRequest> request_;
-  scoped_ptr<InterceptNavigationResourceThrottle> throttle_;
-  MockResourceController throttle_controller_;
-};
-
-// InterceptNavigationResourceThrottleTest ------------------------------------
-
-class InterceptNavigationResourceThrottleTest
-  : public content::RenderViewHostTestHarness {
- public:
-  InterceptNavigationResourceThrottleTest()
-      : mock_callback_receiver_(new MockInterceptCallbackReceiver()),
-        io_thread_state_(NULL) {
-  }
-
-  void SetUp() override { RenderViewHostTestHarness::SetUp(); }
-
-  void TearDown() override {
-    if (web_contents())
-      web_contents()->SetDelegate(NULL);
-
-    content::BrowserThread::DeleteSoon(
-        content::BrowserThread::IO, FROM_HERE, io_thread_state_);
-
-    RenderViewHostTestHarness::TearDown();
-  }
-
-  void SetIOThreadState(TestIOThreadState* io_thread_state) {
-    io_thread_state_ = io_thread_state;
-  }
-
-  void RunThrottleWillStartRequestOnIOThread(
-      const GURL& url,
-      const std::string& request_method,
-      RedirectMode redirect_mode,
-      int render_process_id,
-      int render_frame_id,
-      bool* defer) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-    TestIOThreadState* io_thread_state =
-        new TestIOThreadState(url, render_process_id, render_frame_id,
-                              request_method, redirect_mode,
-                              mock_callback_receiver_.get());
-
-    SetIOThreadState(io_thread_state);
-
-    if (redirect_mode == REDIRECT_MODE_NO_REDIRECT) {
-      io_thread_state->ThrottleWillStartRequest(defer);
-    } else {
-      // 302 redirects convert POSTs to gets.
-      net::RedirectInfo redirect_info;
-      redirect_info.new_url = url;
-      redirect_info.new_method = "GET";
-      io_thread_state->ThrottleWillRedirectRequest(redirect_info, defer);
-    }
-  }
-
- protected:
-  enum ShouldIgnoreNavigationCallbackAction {
-    IgnoreNavigation,
-    DontIgnoreNavigation
-  };
-
-  void SetUpWebContentsDelegateAndDrainRunLoop(
-      ShouldIgnoreNavigationCallbackAction callback_action,
-      bool* defer) {
-    ON_CALL(*mock_callback_receiver_, ShouldIgnoreNavigation(_, _))
-      .WillByDefault(Return(callback_action == IgnoreNavigation));
-    EXPECT_CALL(*mock_callback_receiver_,
-                ShouldIgnoreNavigation(web_contents(),
-                                       NavigationParamsUrlIsTest()))
-      .Times(1);
-
-    content::BrowserThread::PostTask(
-        content::BrowserThread::IO,
-        FROM_HERE,
-        base::Bind(
-            &InterceptNavigationResourceThrottleTest::
-                RunThrottleWillStartRequestOnIOThread,
-            base::Unretained(this),
-            GURL(kTestUrl),
-            "GET",
-            REDIRECT_MODE_NO_REDIRECT,
-            web_contents()->GetRenderViewHost()->GetProcess()->GetID(),
-            web_contents()->GetMainFrame()->GetRoutingID(),
-            base::Unretained(defer)));
-
-    // Wait for the request to finish processing.
-    base::RunLoop().RunUntilIdle();
-  }
-
-  void WaitForPreviouslyScheduledIoThreadWork() {
-    base::WaitableEvent io_thread_work_done(true, false);
-    content::BrowserThread::PostTask(
-        content::BrowserThread::IO,
-        FROM_HERE,
-        base::Bind(
-          &base::WaitableEvent::Signal,
-          base::Unretained(&io_thread_work_done)));
-    io_thread_work_done.Wait();
-  }
-
-  scoped_ptr<MockInterceptCallbackReceiver> mock_callback_receiver_;
-  TestIOThreadState* io_thread_state_;
-};
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       RequestDeferredAndResumedIfNavigationNotIgnored) {
-  bool defer = false;
-  SetUpWebContentsDelegateAndDrainRunLoop(DontIgnoreNavigation, &defer);
-
-  EXPECT_TRUE(defer);
-  ASSERT_TRUE(io_thread_state_);
-  EXPECT_TRUE(io_thread_state_->request_resumed());
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       RequestDeferredAndCancelledIfNavigationIgnored) {
-  bool defer = false;
-  SetUpWebContentsDelegateAndDrainRunLoop(IgnoreNavigation, &defer);
-
-  EXPECT_TRUE(defer);
-  ASSERT_TRUE(io_thread_state_);
-  EXPECT_TRUE(io_thread_state_->request_cancelled());
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       NoCallbackMadeIfContentsDeletedWhileThrottleRunning) {
-  bool defer = false;
-
-  // The tested scenario is when the WebContents is deleted after the
-  // ResourceThrottle has finished processing on the IO thread but before the
-  // UI thread callback has been processed.  Since both threads in this test
-  // are serviced by one message loop, the post order is the execution order.
-  EXPECT_CALL(*mock_callback_receiver_,
-              ShouldIgnoreNavigation(_, _))
-      .Times(0);
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(
-          &InterceptNavigationResourceThrottleTest::
-          RunThrottleWillStartRequestOnIOThread,
-          base::Unretained(this),
-          GURL(kTestUrl),
-          "GET",
-          REDIRECT_MODE_NO_REDIRECT,
-          web_contents()->GetRenderViewHost()->GetProcess()->GetID(),
-          web_contents()->GetMainFrame()->GetRoutingID(),
-          base::Unretained(&defer)));
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::UI,
-      FROM_HERE,
-      base::Bind(
-          &RenderViewHostTestHarness::DeleteContents,
-          base::Unretained(this)));
-
-  // The WebContents will now be deleted and only after that will the UI-thread
-  // callback posted by the ResourceThrottle be executed.
-  base::RunLoop().RunUntilIdle();
-
-  EXPECT_TRUE(defer);
-  ASSERT_TRUE(io_thread_state_);
-  EXPECT_TRUE(io_thread_state_->request_resumed());
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       RequestNotDeferredForRequestNotAssociatedWithARenderView) {
-  bool defer = false;
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(
-          &InterceptNavigationResourceThrottleTest::
-              RunThrottleWillStartRequestOnIOThread,
-          base::Unretained(this),
-          GURL(kTestUrl),
-          "GET",
-          REDIRECT_MODE_NO_REDIRECT,
-          MSG_ROUTING_NONE,
-          MSG_ROUTING_NONE,
-          base::Unretained(&defer)));
-
-  // Wait for the request to finish processing.
-  base::RunLoop().RunUntilIdle();
-
-  EXPECT_FALSE(defer);
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       CallbackCalledWithFilteredUrl) {
-  bool defer = false;
-
-  ON_CALL(*mock_callback_receiver_,
-          ShouldIgnoreNavigation(_, NavigationParamsUrlIsSafe()))
-      .WillByDefault(Return(false));
-  EXPECT_CALL(*mock_callback_receiver_,
-              ShouldIgnoreNavigation(_, NavigationParamsUrlIsSafe()))
-      .Times(1);
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(
-          &InterceptNavigationResourceThrottleTest::
-              RunThrottleWillStartRequestOnIOThread,
-          base::Unretained(this),
-          GURL(kUnsafeTestUrl),
-          "GET",
-          REDIRECT_MODE_NO_REDIRECT,
-          web_contents()->GetRenderViewHost()->GetProcess()->GetID(),
-          web_contents()->GetMainFrame()->GetRoutingID(),
-          base::Unretained(&defer)));
-
-  // Wait for the request to finish processing.
-  base::RunLoop().RunUntilIdle();
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       CallbackIsPostFalseForGet) {
-  bool defer = false;
-
-  EXPECT_CALL(*mock_callback_receiver_,
-              ShouldIgnoreNavigation(_, AllOf(
-                  NavigationParamsUrlIsSafe(),
-                  Property(&NavigationParams::is_post, Eq(false)))))
-      .WillOnce(Return(false));
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(
-          &InterceptNavigationResourceThrottleTest::
-              RunThrottleWillStartRequestOnIOThread,
-          base::Unretained(this),
-          GURL(kTestUrl),
-          "GET",
-          REDIRECT_MODE_NO_REDIRECT,
-          web_contents()->GetRenderViewHost()->GetProcess()->GetID(),
-          web_contents()->GetMainFrame()->GetRoutingID(),
-          base::Unretained(&defer)));
-
-  // Wait for the request to finish processing.
-  base::RunLoop().RunUntilIdle();
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       CallbackIsPostTrueForPost) {
-  bool defer = false;
-
-  EXPECT_CALL(*mock_callback_receiver_,
-              ShouldIgnoreNavigation(_, AllOf(
-                  NavigationParamsUrlIsSafe(),
-                  Property(&NavigationParams::is_post, Eq(true)))))
-      .WillOnce(Return(false));
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(
-          &InterceptNavigationResourceThrottleTest::
-              RunThrottleWillStartRequestOnIOThread,
-          base::Unretained(this),
-          GURL(kTestUrl),
-          "POST",
-          REDIRECT_MODE_NO_REDIRECT,
-          web_contents()->GetRenderViewHost()->GetProcess()->GetID(),
-          web_contents()->GetMainFrame()->GetRoutingID(),
-          base::Unretained(&defer)));
-
-  // Wait for the request to finish processing.
-  base::RunLoop().RunUntilIdle();
-}
-
-TEST_F(InterceptNavigationResourceThrottleTest,
-       CallbackIsPostFalseForPostConvertedToGetBy302) {
-  bool defer = false;
-
-  EXPECT_CALL(*mock_callback_receiver_,
-              ShouldIgnoreNavigation(_, AllOf(
-                  NavigationParamsUrlIsSafe(),
-                  Property(&NavigationParams::is_post, Eq(false)))))
-      .WillOnce(Return(false));
-
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(
-          &InterceptNavigationResourceThrottleTest::
-              RunThrottleWillStartRequestOnIOThread,
-          base::Unretained(this),
-          GURL(kTestUrl),
-          "POST",
-          REDIRECT_MODE_302,
-          web_contents()->GetRenderViewHost()->GetProcess()->GetID(),
-          web_contents()->GetMainFrame()->GetRoutingID(),
-          base::Unretained(&defer)));
-
-  // Wait for the request to finish processing.
-  base::RunLoop().RunUntilIdle();
-}
-
-}  // namespace navigation_interception
diff --git a/components/navigation_interception/intercept_navigation_throttle.cc b/components/navigation_interception/intercept_navigation_throttle.cc
new file mode 100644
index 0000000..cc256a1
--- /dev/null
+++ b/components/navigation_interception/intercept_navigation_throttle.cc
@@ -0,0 +1,49 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/navigation_interception/intercept_navigation_throttle.h"
+
+#include "components/navigation_interception/navigation_params.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_handle.h"
+
+namespace navigation_interception {
+
+InterceptNavigationThrottle::InterceptNavigationThrottle(
+    content::NavigationHandle* navigation_handle,
+    CheckCallback should_ignore_callback)
+    : content::NavigationThrottle(navigation_handle),
+      should_ignore_callback_(should_ignore_callback) {}
+
+InterceptNavigationThrottle::~InterceptNavigationThrottle() {}
+
+content::NavigationThrottle::ThrottleCheckResult
+InterceptNavigationThrottle::WillStartRequest() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  return CheckIfShouldIgnoreNavigation(false);
+}
+
+content::NavigationThrottle::ThrottleCheckResult
+InterceptNavigationThrottle::WillRedirectRequest() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  return CheckIfShouldIgnoreNavigation(true);
+}
+
+content::NavigationThrottle::ThrottleCheckResult
+InterceptNavigationThrottle::CheckIfShouldIgnoreNavigation(bool is_redirect) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  NavigationParams navigation_params(
+      navigation_handle()->GetURL(), navigation_handle()->GetReferrer(),
+      navigation_handle()->HasUserGesture(), navigation_handle()->IsPost(),
+      navigation_handle()->GetPageTransition(), is_redirect,
+      navigation_handle()->IsExternalProtocol(), true);
+
+  bool should_ignore_navigation = should_ignore_callback_.Run(
+      navigation_handle()->GetWebContents(), navigation_params);
+  return should_ignore_navigation
+             ? content::NavigationThrottle::CANCEL_AND_IGNORE
+             : content::NavigationThrottle::PROCEED;
+}
+
+}  // namespace navigation_interception
diff --git a/components/navigation_interception/intercept_navigation_throttle.h b/components/navigation_interception/intercept_navigation_throttle.h
new file mode 100644
index 0000000..0b7f746
--- /dev/null
+++ b/components/navigation_interception/intercept_navigation_throttle.h
@@ -0,0 +1,51 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_
+#define COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/navigation_throttle.h"
+
+class GURL;
+
+namespace content {
+class NavigationHandle;
+class WebContents;
+}
+
+namespace navigation_interception {
+
+class NavigationParams;
+
+// This class allows the provider of the Callback to selectively ignore top
+// level navigations. This is a UI thread class.
+class InterceptNavigationThrottle : public content::NavigationThrottle {
+ public:
+  typedef base::Callback<bool(content::WebContents* /* source */,
+                              const NavigationParams& /* navigation_params */)>
+      CheckCallback;
+
+  InterceptNavigationThrottle(content::NavigationHandle* navigation_handle,
+                              CheckCallback should_ignore_callback);
+  ~InterceptNavigationThrottle() override;
+
+  // content::NavigationThrottle implementation:
+  ThrottleCheckResult WillStartRequest() override;
+  ThrottleCheckResult WillRedirectRequest() override;
+
+ private:
+  ThrottleCheckResult CheckIfShouldIgnoreNavigation(bool is_redirect);
+
+  CheckCallback should_ignore_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterceptNavigationThrottle);
+};
+
+}  // namespace navigation_interception
+
+#endif  // COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_
diff --git a/components/navigation_interception/intercept_navigation_throttle_unittest.cc b/components/navigation_interception/intercept_navigation_throttle_unittest.cc
new file mode 100644
index 0000000..15e05ef
--- /dev/null
+++ b/components/navigation_interception/intercept_navigation_throttle_unittest.cc
@@ -0,0 +1,165 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/memory/scoped_ptr.h"
+#include "components/navigation_interception/intercept_navigation_throttle.h"
+#include "components/navigation_interception/navigation_params.h"
+#include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/test_renderer_host.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using content::NavigationThrottle;
+using testing::_;
+using testing::Eq;
+using testing::Ne;
+using testing::Property;
+using testing::Return;
+
+namespace navigation_interception {
+
+namespace {
+
+const char kTestUrl[] = "http://www.test.com/";
+
+// The MS C++ compiler complains about not being able to resolve which url()
+// method (const or non-const) to use if we use the Property matcher to check
+// the return value of the NavigationParams::url() method.
+// It is possible to suppress the error by specifying the types directly but
+// that results in very ugly syntax, which is why these custom matchers are
+// used instead.
+MATCHER(NavigationParamsUrlIsTest, "") {
+  return arg.url() == GURL(kTestUrl);
+}
+
+}  // namespace
+
+// MockInterceptCallbackReceiver ----------------------------------------------
+
+class MockInterceptCallbackReceiver {
+ public:
+  MOCK_METHOD2(ShouldIgnoreNavigation,
+               bool(content::WebContents* source,
+                    const NavigationParams& navigation_params));
+};
+
+// InterceptNavigationThrottleTest ------------------------------------
+
+class InterceptNavigationThrottleTest
+    : public content::RenderViewHostTestHarness {
+ public:
+  InterceptNavigationThrottleTest()
+      : mock_callback_receiver_(new MockInterceptCallbackReceiver()) {}
+
+  NavigationThrottle::ThrottleCheckResult
+  SimulateWillStart(const GURL& url, const GURL& sanitized_url, bool is_post) {
+    scoped_ptr<content::NavigationHandle> test_handle =
+        content::NavigationHandle::CreateNavigationHandleForTesting(
+            url, true, web_contents());
+    test_handle->RegisterThrottleForTesting(
+        scoped_ptr<NavigationThrottle>(
+            new InterceptNavigationThrottle(
+                test_handle.get(),
+                base::Bind(
+                    &MockInterceptCallbackReceiver::ShouldIgnoreNavigation,
+                    base::Unretained(mock_callback_receiver_.get()))))
+            .Pass());
+    return test_handle->CallWillStartRequestForTesting(
+        is_post, content::Referrer(), false, ui::PAGE_TRANSITION_LINK, false);
+  }
+
+  NavigationThrottle::ThrottleCheckResult Simulate302() {
+    scoped_ptr<content::NavigationHandle> test_handle =
+        content::NavigationHandle::CreateNavigationHandleForTesting(
+            GURL(kTestUrl), true, web_contents());
+    test_handle->RegisterThrottleForTesting(
+        scoped_ptr<NavigationThrottle>(
+            new InterceptNavigationThrottle(
+                test_handle.get(),
+                base::Bind(
+                    &MockInterceptCallbackReceiver::ShouldIgnoreNavigation,
+                    base::Unretained(mock_callback_receiver_.get()))))
+            .Pass());
+    test_handle->CallWillStartRequestForTesting(
+        true, content::Referrer(), false, ui::PAGE_TRANSITION_LINK, false);
+    return test_handle->CallWillRedirectRequestForTesting(GURL(kTestUrl), false,
+                                                          GURL(), false);
+  }
+
+  scoped_ptr<MockInterceptCallbackReceiver> mock_callback_receiver_;
+};
+
+TEST_F(InterceptNavigationThrottleTest,
+       RequestDeferredAndResumedIfNavigationNotIgnored) {
+  ON_CALL(*mock_callback_receiver_, ShouldIgnoreNavigation(_, _))
+      .WillByDefault(Return(false));
+  EXPECT_CALL(
+      *mock_callback_receiver_,
+      ShouldIgnoreNavigation(web_contents(), NavigationParamsUrlIsTest()));
+  NavigationThrottle::ThrottleCheckResult result =
+      SimulateWillStart(GURL(kTestUrl), GURL(kTestUrl), false);
+
+  EXPECT_EQ(NavigationThrottle::PROCEED, result);
+}
+
+TEST_F(InterceptNavigationThrottleTest,
+       RequestDeferredAndCancelledIfNavigationIgnored) {
+  ON_CALL(*mock_callback_receiver_, ShouldIgnoreNavigation(_, _))
+      .WillByDefault(Return(true));
+  EXPECT_CALL(
+      *mock_callback_receiver_,
+      ShouldIgnoreNavigation(web_contents(), NavigationParamsUrlIsTest()));
+  NavigationThrottle::ThrottleCheckResult result =
+      SimulateWillStart(GURL(kTestUrl), GURL(kTestUrl), false);
+
+  EXPECT_EQ(NavigationThrottle::CANCEL_AND_IGNORE, result);
+}
+
+TEST_F(InterceptNavigationThrottleTest, CallbackIsPostFalseForGet) {
+  EXPECT_CALL(*mock_callback_receiver_,
+              ShouldIgnoreNavigation(
+                  _, AllOf(NavigationParamsUrlIsTest(),
+                           Property(&NavigationParams::is_post, Eq(false)))))
+      .WillOnce(Return(false));
+
+  NavigationThrottle::ThrottleCheckResult result =
+      SimulateWillStart(GURL(kTestUrl), GURL(kTestUrl), false);
+
+  EXPECT_EQ(NavigationThrottle::PROCEED, result);
+}
+
+TEST_F(InterceptNavigationThrottleTest, CallbackIsPostTrueForPost) {
+  EXPECT_CALL(*mock_callback_receiver_,
+              ShouldIgnoreNavigation(
+                  _, AllOf(NavigationParamsUrlIsTest(),
+                           Property(&NavigationParams::is_post, Eq(true)))))
+      .WillOnce(Return(false));
+  NavigationThrottle::ThrottleCheckResult result =
+      SimulateWillStart(GURL(kTestUrl), GURL(kTestUrl), true);
+
+  EXPECT_EQ(NavigationThrottle::PROCEED, result);
+}
+
+TEST_F(InterceptNavigationThrottleTest,
+       CallbackIsPostFalseForPostConvertedToGetBy302) {
+  EXPECT_CALL(*mock_callback_receiver_,
+              ShouldIgnoreNavigation(
+                  _, AllOf(NavigationParamsUrlIsTest(),
+                           Property(&NavigationParams::is_post, Eq(true)))))
+      .WillOnce(Return(false));
+  EXPECT_CALL(*mock_callback_receiver_,
+              ShouldIgnoreNavigation(
+                  _, AllOf(NavigationParamsUrlIsTest(),
+                           Property(&NavigationParams::is_post, Eq(false)))))
+      .WillOnce(Return(false));
+  NavigationThrottle::ThrottleCheckResult result = Simulate302();
+
+  EXPECT_EQ(NavigationThrottle::PROCEED, result);
+}
+
+}  // namespace navigation_interception
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index 2c5e773..994a2fc 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -5,6 +5,8 @@
 #include "content/browser/frame_host/navigation_handle_impl.h"
 
 #include "content/browser/frame_host/navigator_delegate.h"
+#include "content/public/browser/content_browser_client.h"
+#include "content/public/common/content_client.h"
 #include "net/url_request/redirect_info.h"
 
 namespace content {
@@ -12,7 +14,7 @@ namespace content {
 // static
 scoped_ptr<NavigationHandleImpl> NavigationHandleImpl::Create(
     const GURL& url,
-    const bool is_main_frame,
+    bool is_main_frame,
     NavigatorDelegate* delegate) {
   return scoped_ptr<NavigationHandleImpl>(
       new NavigationHandleImpl(url, is_main_frame, delegate));
@@ -22,10 +24,14 @@ NavigationHandleImpl::NavigationHandleImpl(const GURL& url,
                                            const bool is_main_frame,
                                            NavigatorDelegate* delegate)
     : url_(url),
-      net_error_code_(net::OK),
-      state_(DID_START),
       is_main_frame_(is_main_frame),
+      is_post_(false),
+      has_user_gesture_(false),
+      transition_(ui::PAGE_TRANSITION_LINK),
+      is_external_protocol_(false),
+      net_error_code_(net::OK),
       is_same_page_(false),
+      state_(INITIAL),
       is_transferring_(false),
       delegate_(delegate) {
   delegate_->DidStartNavigation(this);
@@ -35,16 +41,46 @@ NavigationHandleImpl::~NavigationHandleImpl() {
   delegate_->DidFinishNavigation(this);
 }
 
-const GURL& NavigationHandleImpl::GetURL() const {
+const GURL& NavigationHandleImpl::GetURL() {
   return url_;
 }
 
-net::Error NavigationHandleImpl::GetNetErrorCode() const {
-  return net_error_code_;
+bool NavigationHandleImpl::IsInMainFrame() {
+  return is_main_frame_;
 }
 
-bool NavigationHandleImpl::IsInMainFrame() const {
-  return is_main_frame_;
+bool NavigationHandleImpl::IsPost() {
+  CHECK_NE(INITIAL, state_)
+      << "This accessor should not be called before the request is started.";
+  return is_post_;
+}
+
+const Referrer& NavigationHandleImpl::GetReferrer() {
+  CHECK_NE(INITIAL, state_)
+      << "This accessor should not be called before the request is started.";
+  return sanitized_referrer_;
+}
+
+bool NavigationHandleImpl::HasUserGesture() {
+  CHECK_NE(INITIAL, state_)
+      << "This accessor should not be called before the request is started.";
+  return has_user_gesture_;
+}
+
+ui::PageTransition NavigationHandleImpl::GetPageTransition() {
+  CHECK_NE(INITIAL, state_)
+      << "This accessor should not be called before the request is started.";
+  return transition_;
+}
+
+bool NavigationHandleImpl::IsExternalProtocol() {
+  CHECK_NE(INITIAL, state_)
+      << "This accessor should not be called before the request is started.";
+  return is_external_protocol_;
+}
+
+net::Error NavigationHandleImpl::GetNetErrorCode() {
+  return net_error_code_;
 }
 
 bool NavigationHandleImpl::IsSamePage() {
@@ -54,14 +90,99 @@ bool NavigationHandleImpl::IsSamePage() {
   return is_same_page_;
 }
 
-bool NavigationHandleImpl::HasCommittedDocument() const {
+bool NavigationHandleImpl::HasCommittedDocument() {
   return state_ == DID_COMMIT;
 }
 
-bool NavigationHandleImpl::HasCommittedErrorPage() const {
+bool NavigationHandleImpl::HasCommittedErrorPage() {
   return state_ == DID_COMMIT_ERROR_PAGE;
 }
 
+void NavigationHandleImpl::RegisterThrottleForTesting(
+    scoped_ptr<NavigationThrottle> navigation_throttle) {
+  throttles_.push_back(navigation_throttle.Pass());
+}
+
+NavigationThrottle::ThrottleCheckResult
+NavigationHandleImpl::CallWillStartRequestForTesting(
+    bool is_post,
+    const Referrer& sanitized_referrer,
+    bool has_user_gesture,
+    ui::PageTransition transition,
+    bool is_external_protocol) {
+  return WillStartRequest(is_post, sanitized_referrer, has_user_gesture,
+                          transition, is_external_protocol);
+}
+
+NavigationThrottle::ThrottleCheckResult
+NavigationHandleImpl::CallWillRedirectRequestForTesting(
+    const GURL& new_url,
+    bool new_method_is_post,
+    const GURL& new_referrer_url,
+    bool new_is_external_protocol) {
+  return WillRedirectRequest(new_url, new_method_is_post, new_referrer_url,
+                             new_is_external_protocol);
+}
+
+NavigationThrottle::ThrottleCheckResult NavigationHandleImpl::WillStartRequest(
+    bool is_post,
+    const Referrer& sanitized_referrer,
+    bool has_user_gesture,
+    ui::PageTransition transition,
+    bool is_external_protocol) {
+  // Update the navigation parameters.
+  is_post_ = is_post;
+  sanitized_referrer_ = sanitized_referrer;
+  has_user_gesture_ = has_user_gesture;
+  transition_ = transition;
+  is_external_protocol_ = is_external_protocol;
+
+  state_ = WILL_SEND_REQUEST;
+
+  // Register the navigation throttles. The ScopedVector returned by
+  // GetNavigationThrottles is not assigned to throttles_ directly because it
+  // would overwrite any throttle previously added with
+  // RegisterThrottleForTesting.
+  ScopedVector<NavigationThrottle> throttles_to_register =
+      GetContentClient()->browser()->CreateThrottlesForNavigation(this);
+  if (throttles_to_register.size() > 0) {
+    throttles_.insert(throttles_.end(), throttles_to_register.begin(),
+                      throttles_to_register.end());
+    throttles_to_register.weak_clear();
+  }
+
+  // Notify each throttle of the request.
+  for (NavigationThrottle* throttle : throttles_) {
+    NavigationThrottle::ThrottleCheckResult result =
+        throttle->WillStartRequest();
+    if (result == NavigationThrottle::CANCEL_AND_IGNORE)
+      return NavigationThrottle::CANCEL_AND_IGNORE;
+  }
+  return NavigationThrottle::PROCEED;
+}
+
+NavigationThrottle::ThrottleCheckResult
+NavigationHandleImpl::WillRedirectRequest(const GURL& new_url,
+                                          bool new_method_is_post,
+                                          const GURL& new_referrer_url,
+                                          bool new_is_external_protocol) {
+  // Update the navigation parameters.
+  url_ = new_url;
+  is_post_ = new_method_is_post;
+  sanitized_referrer_.url = new_referrer_url;
+  sanitized_referrer_ = Referrer::SanitizeForRequest(url_, sanitized_referrer_);
+  is_external_protocol_ = new_is_external_protocol;
+
+  // Have each throttle be notified of the request.
+  for (NavigationThrottle* throttle : throttles_) {
+    NavigationThrottle::ThrottleCheckResult result =
+        throttle->WillRedirectRequest();
+    if (result == NavigationThrottle::CANCEL_AND_IGNORE)
+      return NavigationThrottle::CANCEL_AND_IGNORE;
+  }
+  return NavigationThrottle::PROCEED;
+}
+
 void NavigationHandleImpl::DidRedirectNavigation(const GURL& new_url) {
   url_ = new_url;
   delegate_->DidRedirectNavigation(this);
diff --git a/content/browser/frame_host/navigation_handle_impl.h b/content/browser/frame_host/navigation_handle_impl.h
index 861adb0..aebb929 100644
--- a/content/browser/frame_host/navigation_handle_impl.h
+++ b/content/browser/frame_host/navigation_handle_impl.h
@@ -9,7 +9,9 @@
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
 #include "content/common/content_export.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "url/gurl.h"
 
 namespace content {
@@ -53,18 +55,37 @@ struct NavigationRequestInfo;
 class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
  public:
   static scoped_ptr<NavigationHandleImpl> Create(const GURL& url,
-                                                 const bool is_main_frame,
+                                                 bool is_main_frame,
                                                  NavigatorDelegate* delegate);
-
   ~NavigationHandleImpl() override;
 
   // NavigationHandle implementation:
-  const GURL& GetURL() const override;
-  net::Error GetNetErrorCode() const override;
-  bool IsInMainFrame() const override;
+  const GURL& GetURL() override;
+  bool IsInMainFrame() override;
+  bool IsPost() override;
+  const Referrer& GetReferrer() override;
+  bool HasUserGesture() override;
+  ui::PageTransition GetPageTransition() override;
+  bool IsExternalProtocol() override;
+  net::Error GetNetErrorCode() override;
   bool IsSamePage() override;
-  bool HasCommittedDocument() const override;
-  bool HasCommittedErrorPage() const override;
+  bool HasCommittedDocument() override;
+  bool HasCommittedErrorPage() override;
+  void RegisterThrottleForTesting(
+      scoped_ptr<NavigationThrottle> navigation_throttle) override;
+  NavigationThrottle::ThrottleCheckResult CallWillStartRequestForTesting(
+      bool is_post,
+      const Referrer& sanitized_referrer,
+      bool has_user_gesture,
+      ui::PageTransition transition,
+      bool is_external_protocol) override;
+  NavigationThrottle::ThrottleCheckResult CallWillRedirectRequestForTesting(
+      const GURL& new_url,
+      bool new_method_is_post,
+      const GURL& new_referrer_url,
+      bool new_is_external_protocol) override;
+
+  NavigatorDelegate* delegate() const { return delegate_; }
 
   void set_net_error_code(net::Error net_error_code) {
     net_error_code_ = net_error_code;
@@ -79,6 +100,21 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
     is_transferring_ = is_transferring;
   }
 
+  // Called when the URLRequest will start in the network stack.
+  NavigationThrottle::ThrottleCheckResult WillStartRequest(
+      bool is_post,
+      const Referrer& sanitized_referrer,
+      bool has_user_gesture,
+      ui::PageTransition transition,
+      bool is_external_protocol);
+
+  // Called when the URLRequest will be redirected in the network stack.
+  NavigationThrottle::ThrottleCheckResult WillRedirectRequest(
+      const GURL& new_url,
+      bool new_method_is_post,
+      const GURL& new_referrer_url,
+      bool new_is_external_protocol);
+
   // Called when the navigation was redirected. This will update the |url_| and
   // inform the delegate.
   void DidRedirectNavigation(const GURL& new_url);
@@ -90,7 +126,8 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
  private:
   // Used to track the state the navigation is currently in.
   enum State {
-    DID_START = 0,
+    INITIAL = 0,
+    WILL_SEND_REQUEST,
     DID_COMMIT,
     DID_COMMIT_ERROR_PAGE,
   };
@@ -101,11 +138,18 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
 
   // See NavigationHandle for a description of those member variables.
   GURL url_;
-  net::Error net_error_code_;
-  State state_;
   const bool is_main_frame_;
+  bool is_post_;
+  Referrer sanitized_referrer_;
+  bool has_user_gesture_;
+  ui::PageTransition transition_;
+  bool is_external_protocol_;
+  net::Error net_error_code_;
   bool is_same_page_;
 
+  // The state the navigation is in.
+  State state_;
+
   // Whether the navigation is in the middle of a transfer. Set to false when
   // the DidStartProvisionalLoad is received from the new renderer.
   bool is_transferring_;
@@ -114,6 +158,9 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
   // navigation.
   NavigatorDelegate* delegate_;
 
+  // A list of Throttles registered for this navigation.
+  ScopedVector<NavigationThrottle> throttles_;
+
   DISALLOW_COPY_AND_ASSIGN(NavigationHandleImpl);
 };
 
diff --git a/content/browser/frame_host/navigation_request.cc b/content/browser/frame_host/navigation_request.cc
index a99074f..8247f35 100644
--- a/content/browser/frame_host/navigation_request.cc
+++ b/content/browser/frame_host/navigation_request.cc
@@ -14,6 +14,7 @@
 #include "content/browser/site_instance_impl.h"
 #include "content/common/resource_request_body.h"
 #include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/stream_handle.h"
 #include "content/public/common/content_client.h"
 #include "net/base/load_flags.h"
@@ -179,6 +180,20 @@ bool NavigationRequest::BeginNavigation() {
   state_ = STARTED;
 
   if (ShouldMakeNetworkRequestForURL(common_params_.url)) {
+    // TODO(clamy): pass the real value for |is_external_protocol| if needed.
+    NavigationThrottle::ThrottleCheckResult result =
+        navigation_handle_->WillStartRequest(
+            begin_params_.method == "POST",
+            Referrer::SanitizeForRequest(common_params_.url,
+                                         common_params_.referrer),
+            begin_params_.has_user_gesture, common_params_.transition, false);
+
+    // Abort the request if needed. This will destroy the NavigationRequest.
+    if (result == NavigationThrottle::CANCEL_AND_IGNORE) {
+      frame_tree_node_->ResetNavigationRequest(false);
+      return false;
+    }
+
     loader_ = NavigationURLLoader::Create(
         frame_tree_node_->navigator()->GetController()->GetBrowserContext(),
         frame_tree_node_->frame_tree_node_id(), info_.Pass(), this);
@@ -209,12 +224,24 @@ void NavigationRequest::TransferNavigationHandleOwnership(
 void NavigationRequest::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     const scoped_refptr<ResourceResponse>& response) {
-  // TODO(davidben): Track other changes from redirects. These are important
-  // for, e.g., reloads.
   common_params_.url = redirect_info.new_url;
+  begin_params_.method = redirect_info.new_method;
+  common_params_.referrer.url = GURL(redirect_info.new_referrer);
+
+  // TODO(clamy): Have CSP + security upgrade checks here.
+  // TODO(clamy): Kill the renderer if FilterURL fails?
+  // TODO(clamy): pass the real value for |is_external_protocol| if needed.
+  NavigationThrottle::ThrottleCheckResult result =
+      navigation_handle_->WillRedirectRequest(
+          common_params_.url, begin_params_.method == "POST",
+          common_params_.referrer.url, false);
+
+  // Abort the request if needed. This will destroy the NavigationRequest.
+  if (result == NavigationThrottle::CANCEL_AND_IGNORE) {
+    frame_tree_node_->ResetNavigationRequest(false);
+    return;
+  }
 
-  // TODO(davidben): This where prerender and navigation_interceptor should be
-  // integrated. For now, just always follow all redirects.
   loader_->FollowRedirect();
 
   navigation_handle_->DidRedirectNavigation(redirect_info.new_url);
diff --git a/content/browser/frame_host/navigation_request.h b/content/browser/frame_host/navigation_request.h
index a1530b4..b711278 100644
--- a/content/browser/frame_host/navigation_request.h
+++ b/content/browser/frame_host/navigation_request.h
@@ -164,8 +164,10 @@ class CONTENT_EXPORT NavigationRequest : public NavigationURLLoaderDelegate {
   // Note: When the navigation is ready to commit, the url in |common_params|
   // will be set to the final navigation url, obtained after following all
   // redirects.
+  // Note: |common_params_| and |begin_params_| are not const as they can be
+  // modified during redirects.
   CommonNavigationParams common_params_;
-  const BeginNavigationParams begin_params_;
+  BeginNavigationParams begin_params_;
   const RequestNavigationParams request_params_;
   const bool browser_initiated_;
 
diff --git a/content/browser/frame_host/navigator_impl.cc b/content/browser/frame_host/navigator_impl.cc
index b03e232..fa0c049 100644
--- a/content/browser/frame_host/navigator_impl.cc
+++ b/content/browser/frame_host/navigator_impl.cc
@@ -159,7 +159,7 @@ void NavigatorImpl::DidStartProvisionalLoad(
   }
 
   render_frame_host->SetNavigationHandle(
-      NavigationHandleImpl::Create(url, is_main_frame, delegate_));
+      NavigationHandleImpl::Create(validated_url, is_main_frame, delegate_));
 }
 
 void NavigatorImpl::DidFailProvisionalLoadWithError(
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 8f6c99c..aed2daa 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -1359,8 +1359,10 @@ void RenderFrameHostImpl::OnBeginNavigation(
     scoped_refptr<ResourceRequestBody> body) {
   CHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableBrowserSideNavigation));
+  CommonNavigationParams validated_params = common_params;
+  GetProcess()->FilterURL(false, &validated_params.url);
   frame_tree_node()->navigator()->OnBeginNavigation(
-      frame_tree_node(), common_params, begin_params, body);
+      frame_tree_node(), validated_params, begin_params, body);
 }
 
 void RenderFrameHostImpl::OnDispatchLoad() {
diff --git a/content/browser/loader/navigation_resource_throttle.cc b/content/browser/loader/navigation_resource_throttle.cc
new file mode 100644
index 0000000..8dd143c
--- /dev/null
+++ b/content/browser/loader/navigation_resource_throttle.cc
@@ -0,0 +1,154 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/loader/navigation_resource_throttle.h"
+
+#include "base/callback.h"
+#include "content/browser/frame_host/navigation_handle_impl.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
+#include "content/public/browser/resource_context.h"
+#include "content/public/browser/resource_controller.h"
+#include "content/public/browser/resource_request_info.h"
+#include "content/public/common/referrer.h"
+#include "net/url_request/redirect_info.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_context.h"
+#include "net/url_request/url_request_job_factory.h"
+#include "ui/base/page_transition_types.h"
+
+namespace content {
+
+namespace {
+typedef base::Callback<void(NavigationThrottle::ThrottleCheckResult)>
+    UIChecksPerformedCallback;
+
+void CheckWillStartRequestOnUIThread(UIChecksPerformedCallback callback,
+                                     int render_process_id,
+                                     int render_frame_host_id,
+                                     bool is_post,
+                                     const Referrer& sanitized_referrer,
+                                     bool has_user_gesture,
+                                     ui::PageTransition transition,
+                                     bool is_external_protocol) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  NavigationThrottle::ThrottleCheckResult result = NavigationThrottle::PROCEED;
+  RenderFrameHostImpl* render_frame_host =
+      RenderFrameHostImpl::FromID(render_process_id, render_frame_host_id);
+  if (render_frame_host) {
+    NavigationHandleImpl* navigation_handle =
+        render_frame_host->navigation_handle();
+    if (navigation_handle) {
+      result = navigation_handle->WillStartRequest(is_post, sanitized_referrer,
+                                                   has_user_gesture, transition,
+                                                   is_external_protocol);
+    }
+  }
+  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+                          base::Bind(callback, result));
+}
+
+void CheckWillRedirectRequestOnUIThread(UIChecksPerformedCallback callback,
+                                        int render_process_id,
+                                        int render_frame_host_id,
+                                        const GURL& new_url,
+                                        bool new_method_is_post,
+                                        const GURL& new_referrer_url,
+                                        bool new_is_external_protocol) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  NavigationThrottle::ThrottleCheckResult result = NavigationThrottle::PROCEED;
+  RenderFrameHostImpl* render_frame_host =
+      RenderFrameHostImpl::FromID(render_process_id, render_frame_host_id);
+  if (render_frame_host) {
+    NavigationHandleImpl* navigation_handle =
+        render_frame_host->navigation_handle();
+    if (navigation_handle) {
+      RenderProcessHost* rph = RenderProcessHost::FromID(render_process_id);
+      GURL new_validated_url = new_url;
+      rph->FilterURL(false, &new_validated_url);
+      result = navigation_handle->WillRedirectRequest(
+          new_validated_url, new_method_is_post, new_referrer_url,
+          new_is_external_protocol);
+    }
+  }
+  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+                          base::Bind(callback, result));
+}
+}  // namespace
+
+NavigationResourceThrottle::NavigationResourceThrottle(net::URLRequest* request)
+    : request_(request), weak_ptr_factory_(this) {}
+
+NavigationResourceThrottle::~NavigationResourceThrottle() {}
+
+void NavigationResourceThrottle::WillStartRequest(bool* defer) {
+  const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request_);
+  if (!info)
+    return;
+
+  int render_process_id, render_frame_id;
+  if (!info->GetAssociatedRenderFrame(&render_process_id, &render_frame_id))
+    return;
+
+  bool is_external_protocol =
+      !info->GetContext()->GetRequestContext()->job_factory()->IsHandledURL(
+          request_->url());
+  UIChecksPerformedCallback callback =
+      base::Bind(&NavigationResourceThrottle::OnUIChecksPerformed,
+                 weak_ptr_factory_.GetWeakPtr());
+  DCHECK(request_->method() == "POST" || request_->method() == "GET");
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&CheckWillStartRequestOnUIThread, callback, render_process_id,
+                 render_frame_id, request_->method() == "POST",
+                 Referrer::SanitizeForRequest(
+                     request_->url(), Referrer(GURL(request_->referrer()),
+                                               info->GetReferrerPolicy())),
+                 info->HasUserGesture(), info->GetPageTransition(),
+                 is_external_protocol));
+  *defer = true;
+}
+
+void NavigationResourceThrottle::WillRedirectRequest(
+    const net::RedirectInfo& redirect_info,
+    bool* defer) {
+  const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request_);
+  if (!info)
+    return;
+
+  int render_process_id, render_frame_id;
+  if (!info->GetAssociatedRenderFrame(&render_process_id, &render_frame_id))
+    return;
+
+  bool new_is_external_protocol =
+      !info->GetContext()->GetRequestContext()->job_factory()->IsHandledURL(
+          request_->url());
+  DCHECK(redirect_info.new_method == "POST" ||
+         redirect_info.new_method == "GET");
+  UIChecksPerformedCallback callback =
+      base::Bind(&NavigationResourceThrottle::OnUIChecksPerformed,
+                 weak_ptr_factory_.GetWeakPtr());
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&CheckWillRedirectRequestOnUIThread, callback,
+                 render_process_id, render_frame_id, redirect_info.new_url,
+                 redirect_info.new_method == "POST",
+                 GURL(redirect_info.new_referrer), new_is_external_protocol));
+  *defer = true;
+}
+
+const char* NavigationResourceThrottle::GetNameForLogging() const {
+  return "NavigationResourceThrottle";
+}
+
+void NavigationResourceThrottle::OnUIChecksPerformed(
+    NavigationThrottle::ThrottleCheckResult result) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (result == NavigationThrottle::CANCEL_AND_IGNORE) {
+    controller()->CancelAndIgnore();
+  } else {
+    controller()->Resume();
+  }
+}
+
+}  // namespace content
diff --git a/content/browser/loader/navigation_resource_throttle.h b/content/browser/loader/navigation_resource_throttle.h
new file mode 100644
index 0000000..e46b59d
--- /dev/null
+++ b/content/browser/loader/navigation_resource_throttle.h
@@ -0,0 +1,44 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
+#define CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
+
+#include "base/basictypes.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "content/public/browser/resource_throttle.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace content {
+
+// This ResourceThrottle is used to convey throttling information to the UI
+// thread during navigations. The UI thread can then use its NavigationThrottle
+// mechanism to interact with the navigation.
+class NavigationResourceThrottle : public ResourceThrottle {
+ public:
+  NavigationResourceThrottle(net::URLRequest* request);
+  ~NavigationResourceThrottle() override;
+
+  // ResourceThrottle overrides:
+  void WillStartRequest(bool* defer) override;
+  void WillRedirectRequest(const net::RedirectInfo& redirect_info,
+                           bool* defer) override;
+  const char* GetNameForLogging() const override;
+
+ private:
+  void OnUIChecksPerformed(NavigationThrottle::ThrottleCheckResult result);
+
+  net::URLRequest* request_;
+  base::WeakPtrFactory<NavigationResourceThrottle> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(NavigationResourceThrottle);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index c5c6796..81cbf8a 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -41,6 +41,7 @@
 #include "content/browser/loader/detachable_resource_handler.h"
 #include "content/browser/loader/mime_type_resource_handler.h"
 #include "content/browser/loader/navigation_resource_handler.h"
+#include "content/browser/loader/navigation_resource_throttle.h"
 #include "content/browser/loader/navigation_url_loader_impl_core.h"
 #include "content/browser/loader/power_save_block_resource_throttle.h"
 #include "content/browser/loader/redirect_to_file_resource_handler.h"
@@ -1481,6 +1482,16 @@ scoped_ptr<ResourceHandler> ResourceDispatcherHostImpl::AddStandardHandlers(
                                             plugin_service, request));
 
   ScopedVector<ResourceThrottle> throttles;
+
+  // Add a NavigationResourceThrottle for navigations.
+  // PlzNavigate: the throttle is unnecessary as communication with the UI
+  // thread is handled by the NavigationURLloader.
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation) &&
+      IsResourceTypeFrame(resource_type)) {
+    throttles.push_back(new NavigationResourceThrottle(request));
+  }
+
   if (delegate_) {
     delegate_->RequestBeginning(request,
                                 resource_context,
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 182628e..f562da9 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -182,7 +182,10 @@
       'public/browser/navigation_details.cc',
       'public/browser/navigation_details.h',
       'public/browser/navigation_entry.h',
+      'public/browser/navigation_handle.cc',
       'public/browser/navigation_handle.h',
+      'public/browser/navigation_throttle.cc',
+      'public/browser/navigation_throttle.h',
       'public/browser/navigation_type.h',
       'public/browser/navigator_connect_context.h',
       'public/browser/navigator_connect_service_factory.h',
@@ -972,6 +975,8 @@
       'browser/loader/mime_type_resource_handler.h',
       'browser/loader/navigation_resource_handler.cc',
       'browser/loader/navigation_resource_handler.h',
+      'browser/loader/navigation_resource_throttle.cc',
+      'browser/loader/navigation_resource_throttle.h',
       'browser/loader/navigation_url_loader.cc',
       'browser/loader/navigation_url_loader.h',
       'browser/loader/navigation_url_loader_delegate.h',
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 01b58bd..f25c84a 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -359,6 +359,12 @@ void ContentBrowserClient::OpenURL(
   callback.Run(nullptr);
 }
 
+ScopedVector<NavigationThrottle>
+ContentBrowserClient::CreateThrottlesForNavigation(
+    NavigationHandle* navigation_handle) {
+  return ScopedVector<NavigationThrottle>();
+}
+
 #if defined(OS_WIN)
 const wchar_t* ContentBrowserClient::GetResourceDllName() {
   return nullptr;
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index 2c6734c..55569fb 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -16,6 +16,7 @@
 #include "base/memory/scoped_vector.h"
 #include "base/values.h"
 #include "content/public/browser/certificate_request_result_type.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/media_stream_request.h"
 #include "content/public/common/resource_type.h"
@@ -96,6 +97,7 @@ class DevToolsManagerDelegate;
 class ExternalVideoSurfaceContainer;
 class LocationProvider;
 class MediaObserver;
+class NavigationHandle;
 class NavigatorConnectContext;
 class NavigatorConnectServiceFactory;
 class PlatformNotificationService;
@@ -669,6 +671,14 @@ class CONTENT_EXPORT ContentBrowserClient {
   // Allows the embedder to record |metric| for a specific |url|.
   virtual void RecordURLMetric(const std::string& metric, const GURL& url) {}
 
+  // Allows the embedder to register one or more NavigationThrottles for the
+  // navigation indicated by |navigation_handle|.  A NavigationThrottle is used
+  // to control the flow of a navigation on the UI thread. The embedder is
+  // guaranteed that the throttles will be executed in the order they were
+  // provided.
+  virtual ScopedVector<NavigationThrottle> CreateThrottlesForNavigation(
+      NavigationHandle* navigation_handle);
+
   // Populates |mappings| with all files that need to be mapped before launching
   // a child process.
 #if defined(OS_ANDROID)
diff --git a/content/public/browser/navigation_handle.cc b/content/public/browser/navigation_handle.cc
new file mode 100644
index 0000000..f5eaa11
--- /dev/null
+++ b/content/public/browser/navigation_handle.cc
@@ -0,0 +1,30 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/public/browser/navigation_handle.h"
+
+#include "content/browser/frame_host/navigation_handle_impl.h"
+#include "content/browser/frame_host/navigator.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+
+namespace content {
+
+WebContents* NavigationHandle::GetWebContents() {
+  // The NavigationHandleImpl cannot access the WebContentsImpl as it would be
+  // a layering violation, hence the cast here.
+  return static_cast<WebContentsImpl*>(
+      static_cast<NavigationHandleImpl*>(this)->delegate());
+}
+
+// static
+scoped_ptr<NavigationHandle> NavigationHandle::CreateNavigationHandleForTesting(
+    const GURL& url,
+    bool is_main_frame,
+    WebContents* web_contents) {
+  scoped_ptr<NavigationHandleImpl> handle_impl = NavigationHandleImpl::Create(
+      url, is_main_frame, static_cast<WebContentsImpl*>(web_contents));
+  return scoped_ptr<NavigationHandle>(handle_impl.Pass());
+}
+
+}  // namespace content
diff --git a/content/public/browser/navigation_handle.h b/content/public/browser/navigation_handle.h
index c60baba..033aca2 100644
--- a/content/public/browser/navigation_handle.h
+++ b/content/public/browser/navigation_handle.h
@@ -6,27 +6,70 @@
 #define CONTENT_PUBLIC_BROWSER_NAVIGATION_HANDLE_H_
 
 #include "content/common/content_export.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "content/public/common/referrer.h"
 #include "net/base/net_errors.h"
+#include "ui/base/page_transition_types.h"
 
 class GURL;
 
 namespace content {
+class NavigationThrottle;
+class WebContents;
 
 // A NavigationHandle tracks information related to a single navigation.
 class CONTENT_EXPORT NavigationHandle {
  public:
   virtual ~NavigationHandle() {}
 
+  // Parameters available at navigation start time -----------------------------
+  //
+  // These parameters are always available during the navigation. Note that
+  // some may change during navigation (e.g. due to server redirects).
+
   // The URL the frame is navigating to. This may change during the navigation
   // when encountering a server redirect.
-  virtual const GURL& GetURL() const = 0;
+  virtual const GURL& GetURL() = 0;
+
+  // Whether the navigation is taking place in the main frame or in a subframe.
+  // This remains constant over the navigation lifetime.
+  virtual bool IsInMainFrame() = 0;
+
+  // The WebContents the navigation is taking place in.
+  WebContents* GetWebContents();
+
+  // Parameters available at network request start time ------------------------
+  //
+  // The following parameters are only available when the network request is
+  // made for the navigation (or at commit time if no network request is made).
+  // This corresponds to NavigationThrottle::WillSendRequest. They should not
+  // be queried before that.
+
+  // Whether the navigation is a POST or a GET. This may change during the
+  // navigation when encountering a server redirect.
+  virtual bool IsPost() = 0;
+
+  // Returns a sanitized version of the referrer for this request.
+  virtual const Referrer& GetReferrer() = 0;
+
+  // Whether the navigation was initiated by a user gesture. Note that this
+  // will return false for browser-initiated navigations.
+  // TODO(clamy): when PlzNavigate launches, this should return true for
+  // browser-initiated navigations.
+  virtual bool HasUserGesture() = 0;
+
+  // Returns the page transition type.
+  virtual ui::PageTransition GetPageTransition() = 0;
+
+  // Whether the target URL cannot be handled by the browser's internal protocol
+  // handlers.
+  virtual bool IsExternalProtocol() = 0;
+
+  // Navigation control flow --------------------------------------------------
 
   // The net error code if an error happened prior to commit. Otherwise it will
   // be net::OK.
-  virtual net::Error GetNetErrorCode() const = 0;
-
-  // Whether the navigation is taking place in the main frame or in a subframe.
-  virtual bool IsInMainFrame() const = 0;
+  virtual net::Error GetNetErrorCode() = 0;
 
   // Whether the navigation happened in the same page. This is only known
   // after the navigation has committed. It is an error to call this method
@@ -34,10 +77,44 @@ class CONTENT_EXPORT NavigationHandle {
   virtual bool IsSamePage() = 0;
 
   // Whether the navigation has successfully committed a document.
-  virtual bool HasCommittedDocument() const = 0;
+  virtual bool HasCommittedDocument() = 0;
 
   // Whether an error page has committed for the navigation.
-  virtual bool HasCommittedErrorPage() const = 0;
+  virtual bool HasCommittedErrorPage() = 0;
+
+  // Testing methods ----------------------------------------------------------
+  //
+  // The following methods should be used exclusively for writing unit tests.
+
+  static scoped_ptr<NavigationHandle> CreateNavigationHandleForTesting(
+      const GURL& url,
+      bool is_main_frame,
+      WebContents* web_contents);
+
+  // Registers a NavigationThrottle for tests. The throttle can
+  // modify the request, pause the request or cancel the request. This will
+  // take ownership of the NavigationThrottle.
+  // Note: in non-test cases, NavigationThrottles should not be added directly
+  // but returned by the implementation of
+  // ContentBrowserClient::CreateThrottlesForNavigation. This ensures proper
+  // ordering of the throttles.
+  virtual void RegisterThrottleForTesting(
+      scoped_ptr<NavigationThrottle> navigation_throttle) = 0;
+
+  // Simulates the network request starting.
+  virtual NavigationThrottle::ThrottleCheckResult
+  CallWillStartRequestForTesting(bool is_post,
+                                 const Referrer& sanitized_referrer,
+                                 bool has_user_gesture,
+                                 ui::PageTransition transition,
+                                 bool is_external_protocol) = 0;
+
+  // Simulates the network request being redirected.
+  virtual NavigationThrottle::ThrottleCheckResult
+  CallWillRedirectRequestForTesting(const GURL& new_url,
+                                    bool new_method_is_post,
+                                    const GURL& new_referrer_url,
+                                    bool new_is_external_protocol) = 0;
 };
 
 }  // namespace content
diff --git a/content/public/browser/navigation_throttle.cc b/content/public/browser/navigation_throttle.cc
new file mode 100644
index 0000000..ac3b3aa
--- /dev/null
+++ b/content/public/browser/navigation_throttle.cc
@@ -0,0 +1,23 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/public/browser/navigation_throttle.h"
+
+namespace content {
+
+NavigationThrottle::NavigationThrottle(NavigationHandle* navigation_handle)
+    : navigation_handle_(navigation_handle) {}
+
+NavigationThrottle::~NavigationThrottle() {}
+
+NavigationThrottle::ThrottleCheckResult NavigationThrottle::WillStartRequest() {
+  return NavigationThrottle::PROCEED;
+}
+
+NavigationThrottle::ThrottleCheckResult
+NavigationThrottle::WillRedirectRequest() {
+  return NavigationThrottle::PROCEED;
+}
+
+}  // namespace content
diff --git a/content/public/browser/navigation_throttle.h b/content/public/browser/navigation_throttle.h
new file mode 100644
index 0000000..ae5883b
--- /dev/null
+++ b/content/public/browser/navigation_throttle.h
@@ -0,0 +1,43 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_PUBLIC_BROWSER_NAVIGATION_THROTTLE_H_
+#define CONTENT_PUBLIC_BROWSER_NAVIGATION_THROTTLE_H_
+
+#include "content/common/content_export.h"
+
+namespace content {
+class NavigationHandle;
+
+// A NavigationThrottle tracks and allows interaction with a navigation on the
+// UI thread.
+class CONTENT_EXPORT NavigationThrottle {
+ public:
+  // This is returned to the NavigationHandle to allow the navigation to
+  // proceed, or to cancel it.
+  enum ThrottleCheckResult {
+    PROCEED,
+    CANCEL_AND_IGNORE,
+  };
+
+  NavigationThrottle(NavigationHandle* navigation_handle);
+  virtual ~NavigationThrottle();
+
+  // Called when a network request is about to be made for this navigation.
+  virtual ThrottleCheckResult WillStartRequest();
+
+  // Called when a server redirect is received by the navigation.
+  virtual ThrottleCheckResult WillRedirectRequest();
+
+  // The NavigationHandle that is tracking the information related to this
+  // navigation.
+  NavigationHandle* navigation_handle() const { return navigation_handle_; }
+
+ private:
+  NavigationHandle* navigation_handle_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_NAVIGATION_THROTTLE_H_
diff --git a/content/test/web_contents_observer_sanity_checker.cc b/content/test/web_contents_observer_sanity_checker.cc
index 82bcb60..18d38ae 100644
--- a/content/test/web_contents_observer_sanity_checker.cc
+++ b/content/test/web_contents_observer_sanity_checker.cc
@@ -129,6 +129,7 @@ void WebContentsObserverSanityChecker::DidStartNavigation(
   CHECK(navigation_handle->GetNetErrorCode() == net::OK);
   CHECK(!navigation_handle->HasCommittedDocument());
   CHECK(!navigation_handle->HasCommittedErrorPage());
+  CHECK_EQ(navigation_handle->GetWebContents(), web_contents());
 
   ongoing_navigations_.insert(navigation_handle);
 }
@@ -141,6 +142,7 @@ void WebContentsObserverSanityChecker::DidRedirectNavigation(
   CHECK(navigation_handle->GetNetErrorCode() == net::OK);
   CHECK(!navigation_handle->HasCommittedDocument());
   CHECK(!navigation_handle->HasCommittedErrorPage());
+  CHECK_EQ(navigation_handle->GetWebContents(), web_contents());
 }
 
 void WebContentsObserverSanityChecker::ReadyToCommitNavigation(
@@ -163,6 +165,7 @@ void WebContentsObserverSanityChecker::DidCommitNavigation(
                 navigation_handle->GetNetErrorCode() == net::OK);
   CHECK_IMPLIES(navigation_handle->HasCommittedErrorPage(),
                 navigation_handle->GetNetErrorCode() != net::OK);
+  CHECK_EQ(navigation_handle->GetWebContents(), web_contents());
 
   ongoing_committed_navigations_.insert(navigation_handle);
 }
@@ -178,6 +181,7 @@ void WebContentsObserverSanityChecker::DidFinishNavigation(
                 navigation_handle->GetNetErrorCode() == net::OK);
   CHECK_IMPLIES(navigation_handle->HasCommittedErrorPage(),
                 navigation_handle->GetNetErrorCode() != net::OK);
+  CHECK_EQ(navigation_handle->GetWebContents(), web_contents());
 
   if (NavigationIsOngoingAndCommitted(navigation_handle))
     ongoing_committed_navigations_.erase(navigation_handle);