Reinstate linkable ephemeral apps experiment

Reverts https://codereview.chromium.org/100553002
Reason for revert: The reverted patch was requested by the security
team, but there was a misunderstanding about whether this was a finch
experiment or a feature behind command line flags.

There is one difference with the original patch:
This patch restricts the ability to launch ephemeral apps to
https://www.google.com (previously allowed both http and https).

The "enable-linkable-ephemeral-apps" command line flag still must
be enabled.

BUG=312460
TBR=sky@chromium.org, benwells@chromium.org

Review URL: https://codereview.chromium.org/100133005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241807 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 114 insertions, 0 deletions

diff --git a/chrome/browser/apps/ephemeral_app_throttle.cc b/chrome/browser/apps/ephemeral_app_throttle.cc
new file mode 100644
index 0000000..fafda3f
--- /dev/null
+++ b/chrome/browser/apps/ephemeral_app_throttle.cc
@@ -0,0 +1,114 @@
+// Copyright 2013 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 "chrome/browser/apps/ephemeral_app_throttle.h"
+
+#include "base/command_line.h"
+#include "chrome/browser/apps/ephemeral_app_launcher.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_io_data.h"
+#include "chrome/browser/ui/extensions/application_launch.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/extensions/extension_constants.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_view_host.h"
+#include "content/public/browser/resource_throttle.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_view.h"
+#include "net/url_request/url_request.h"
+
+using content::BrowserThread;
+using content::WebContents;
+using extensions::Extension;
+
+namespace {
+
+bool LaunchEphemeralApp(
+    const std::string& app_id,
+    content::RenderViewHost* source,
+    const navigation_interception::NavigationParams& params) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Redirect top-level navigations only.
+  if (source->IsSubframe())
+    return false;
+
+  WebContents* web_contents = WebContents::FromRenderViewHost(source);
+  if (!web_contents)
+    return false;
+
+  Profile* profile =
+      Profile::FromBrowserContext(web_contents->GetBrowserContext());
+  if (!profile)
+    return false;
+
+  ExtensionService* service =
+      extensions::ExtensionSystem::Get(profile)->extension_service();
+  DCHECK(service);
+  const Extension* extension = service->GetExtensionById(app_id, false);
+
+  if (extension && extension->is_app()) {
+    // If the app is already installed, launch it.
+    AppLaunchParams params(profile, extension, NEW_FOREGROUND_TAB);
+    params.desktop_type = chrome::GetHostDesktopTypeForNativeView(
+        web_contents->GetView()->GetNativeView());
+    OpenApplication(params);
+    return true;
+  }
+
+  if (!extension) {
+    // Install ephemeral app and launch.
+    scoped_refptr<EphemeralAppLauncher> installer =
+        EphemeralAppLauncher::CreateForLink(app_id, web_contents);
+    installer->Start();
+    return true;
+  }
+
+  return false;
+}
+
+}  // namespace
+
+// static
+content::ResourceThrottle*
+EphemeralAppThrottle::MaybeCreateThrottleForLaunch(
+    net::URLRequest* request,
+    ProfileIOData* profile_io_data) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableLinkableEphemeralApps))
+    return NULL;
+
+  if (request->method() != "GET" || !request->url().SchemeIsHTTPOrHTTPS())
+    return NULL;
+
+  // Not supported for incognito profiles.
+  if (profile_io_data->is_incognito())
+    return NULL;
+
+  // Only watch for links in Google search results.
+  if (request->referrer().find("https://www.google.com") == std::string::npos)
+    return NULL;
+
+  // Crudely watch for links to Chrome Web Store detail pages and assume that
+  // the app ID will be after the last slash of the URL. We cannot even
+  // differentiate between apps and extensions, so attempt to launch both.
+  // This is obviously for demonstration purposes only and will be implemented
+  // properly in production code - for example, links to ephemeral apps could
+  // have a new scheme.
+  if (request->url().spec().find(
+          extension_urls::GetWebstoreItemDetailURLPrefix()) != 0)
+    return NULL;
+
+  std::string app_id(request->url().ExtractFileName());
+  if (!Extension::IdIsValid(app_id))
+    return NULL;
+
+  return new navigation_interception::InterceptNavigationResourceThrottle(
+      request,
+      base::Bind(&LaunchEphemeralApp, app_id));
+}