Extract some stuff into PackageManager:

- content handler determination from ApplicationManager::HandleFetchCallback
- content handler registration
- renames BaseApplicationFetcher to PackageManagerImpl.

R=yzshen@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1352663002

Cr-Commit-Position: refs/heads/master@{#349357}

27 files changed, 558 insertions, 371 deletions

diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index 212acbe..599a555 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -39,7 +39,7 @@ source_set("browser") {
     "//mojo/application/public/cpp:cpp_for_chromium",
     "//mojo/application/public/interfaces",
     "//mojo/common",
-    "//mojo/fetcher",
+    "//mojo/package_manager",
     "//mojo/shell",
     "//net",
     "//net:extras",
diff --git a/content/browser/mojo/mojo_shell_context.cc b/content/browser/mojo/mojo_shell_context.cc
index 80120da..45d2273 100644
--- a/content/browser/mojo/mojo_shell_context.cc
+++ b/content/browser/mojo/mojo_shell_context.cc
@@ -18,7 +18,7 @@
 #include "content/public/common/service_registry.h"
 #include "mojo/application/public/cpp/application_delegate.h"
 #include "mojo/common/url_type_converters.h"
-#include "mojo/fetcher/base_application_fetcher.h"
+#include "mojo/package_manager/package_manager_impl.h"
 #include "mojo/shell/application_loader.h"
 #include "mojo/shell/connect_to_application_params.h"
 #include "mojo/shell/identity.h"
@@ -159,10 +159,10 @@ MojoShellContext::MojoShellContext() {
 
   // Construct with an empty filepath since mojo: urls can't be registered now
   // the url scheme registry is locked.
-  scoped_ptr<mojo::fetcher::BaseApplicationFetcher> fetcher(
-      new mojo::fetcher::BaseApplicationFetcher(base::FilePath()));
+  scoped_ptr<mojo::package_manager::PackageManagerImpl> package_manager(
+      new mojo::package_manager::PackageManagerImpl(base::FilePath()));
   application_manager_.reset(
-      new mojo::shell::ApplicationManager(fetcher.Pass()));
+      new mojo::shell::ApplicationManager(package_manager.Pass()));
 
   application_manager_->set_default_loader(
       scoped_ptr<mojo::shell::ApplicationLoader>(new DefaultApplicationLoader));
diff --git a/mandoline/app/android/BUILD.gn b/mandoline/app/android/BUILD.gn
index 4afc198..20c3fac 100644
--- a/mandoline/app/android/BUILD.gn
+++ b/mandoline/app/android/BUILD.gn
@@ -24,6 +24,7 @@ executable("mandoline_runner") {
     "//mandoline/ui/desktop_ui/public/interfaces",
     "//mojo/common",
     "//mojo/environment:chromium",
+    "//mojo/package_manager",
     "//mojo/runner:lib",
     "//mojo/runner:mojo_runner_lib",
   ]
diff --git a/mandoline/app/core_services_initialization.cc b/mandoline/app/core_services_initialization.cc
index 17ee8f0..b56343d 100644
--- a/mandoline/app/core_services_initialization.cc
+++ b/mandoline/app/core_services_initialization.cc
@@ -4,6 +4,7 @@
 
 #include "mandoline/app/core_services_initialization.h"
 
+#include "mojo/package_manager/package_manager_impl.h"
 #include "mojo/runner/context.h"
 
 namespace mandoline {
@@ -11,7 +12,8 @@ namespace mandoline {
 void InitCoreServicesForContext(mojo::runner::Context* context) {
   // TODO(erg): We should probably handle this differently; these could be
   // autogenerated from package manifests.
-  mojo::shell::ApplicationManager* manager = context->application_manager();
+  mojo::package_manager::PackageManagerImpl* manager =
+      context->package_manager();
   manager->RegisterApplicationPackageAlias(
       GURL("mojo:clipboard"), GURL("mojo:core_services"), "Core");
   manager->RegisterApplicationPackageAlias(GURL("mojo:filesystem"),
diff --git a/mandoline/app/desktop/BUILD.gn b/mandoline/app/desktop/BUILD.gn
index ca2140d..6860a0d 100644
--- a/mandoline/app/desktop/BUILD.gn
+++ b/mandoline/app/desktop/BUILD.gn
@@ -22,6 +22,7 @@ executable("mandoline") {
     "//components/tracing:startup_tracing",
     "//mojo/common",
     "//mojo/environment:chromium",
+    "//mojo/package_manager",
     "//mojo/runner:lib",
   ]
 
diff --git a/mojo/fetcher/BUILD.gn b/mojo/fetcher/BUILD.gn
index f362129..c1a49bc 100644
--- a/mojo/fetcher/BUILD.gn
+++ b/mojo/fetcher/BUILD.gn
@@ -8,8 +8,6 @@ source_set("fetcher") {
   sources = [
     "about_fetcher.cc",
     "about_fetcher.h",
-    "base_application_fetcher.cc",
-    "base_application_fetcher.h",
     "local_fetcher.cc",
     "local_fetcher.h",
     "network_fetcher.cc",
diff --git a/mojo/fetcher/about_fetcher_unittest.cc b/mojo/fetcher/about_fetcher_unittest.cc
index 79c487a..b69d349 100644
--- a/mojo/fetcher/about_fetcher_unittest.cc
+++ b/mojo/fetcher/about_fetcher_unittest.cc
@@ -15,7 +15,7 @@
 #include "mojo/application/public/interfaces/content_handler.mojom.h"
 #include "mojo/common/weak_binding_set.h"
 #include "mojo/fetcher/about_fetcher.h"
-#include "mojo/fetcher/base_application_fetcher.h"
+#include "mojo/package_manager/package_manager_impl.h"
 #include "mojo/runner/context.h"
 #include "mojo/shell/application_loader.h"
 #include "mojo/shell/application_manager.h"
@@ -125,13 +125,15 @@ class AboutFetcherTest : public testing::Test {
     runner::Context::EnsureEmbedderIsInitialized();
     base::FilePath shell_dir;
     PathService::Get(base::DIR_MODULE, &shell_dir);
-    application_manager_.reset(new shell::ApplicationManager(
-        make_scoped_ptr(new BaseApplicationFetcher(shell_dir))));
+    scoped_ptr<package_manager::PackageManagerImpl> package_manager(
+        new package_manager::PackageManagerImpl(shell_dir));
+    package_manager->RegisterContentHandler(
+        "text/html", GURL("test:html_content_handler"));
+    application_manager_.reset(
+        new shell::ApplicationManager(package_manager.Pass()));
     application_manager_->SetLoaderForURL(
         make_scoped_ptr(new TestLoader(&html_content_handler_)),
         GURL("test:html_content_handler"));
-    application_manager_->RegisterContentHandler(
-        "text/html", GURL("test:html_content_handler"));
   }
 
   void TearDown() override { application_manager_.reset(); }
diff --git a/mojo/fetcher/base_application_fetcher.cc b/mojo/fetcher/base_application_fetcher.cc
deleted file mode 100644
index 68909b5..0000000
--- a/mojo/fetcher/base_application_fetcher.cc
+++ /dev/null
@@ -1,99 +0,0 @@
-// 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 "mojo/fetcher/base_application_fetcher.h"
-
-#include "mojo/fetcher/about_fetcher.h"
-#include "mojo/fetcher/local_fetcher.h"
-#include "mojo/fetcher/network_fetcher.h"
-#include "mojo/fetcher/switches.h"
-#include "mojo/fetcher/update_fetcher.h"
-#include "mojo/shell/application_manager.h"
-#include "mojo/shell/query_util.h"
-#include "mojo/util/filename_util.h"
-#include "url/gurl.h"
-
-namespace mojo {
-namespace fetcher {
-
-BaseApplicationFetcher::BaseApplicationFetcher(
-    const base::FilePath& shell_file_root)
-    : application_manager_(nullptr),
-      disable_cache_(base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kDisableCache)) {
-  if (!shell_file_root.empty()) {
-    GURL mojo_root_file_url =
-        util::FilePathToFileURL(shell_file_root).Resolve(std::string());
-    url_resolver_.reset(new URLResolver(mojo_root_file_url));
-  }
-}
-
-BaseApplicationFetcher::~BaseApplicationFetcher() {
-}
-
-void BaseApplicationFetcher::SetApplicationManager(
-    shell::ApplicationManager* manager) {
-  application_manager_ = manager;
-}
-
-GURL BaseApplicationFetcher::ResolveURL(const GURL& url) {
-  return url_resolver_.get() ? url_resolver_->ResolveMojoURL(url) : url;
-}
-
-void BaseApplicationFetcher::FetchRequest(
-    URLRequestPtr request,
-    const shell::Fetcher::FetchCallback& loader_callback) {
-  GURL url(request->url);
-  if (url.SchemeIs(AboutFetcher::kAboutScheme)) {
-    AboutFetcher::Start(url, loader_callback);
-    return;
-  }
-
-  GURL resolved_url = ResolveURL(url);
-
-  if (resolved_url.SchemeIsFile()) {
-    // LocalFetcher uses the network service to infer MIME types from URLs.
-    // Skip this for mojo URLs to avoid recursively loading the network service.
-    if (!network_service_ && !url.SchemeIs("mojo")) {
-      application_manager_->ConnectToService(GURL("mojo:network_service"),
-                                            &network_service_);
-    }
-    // Ownership of this object is transferred to |loader_callback|.
-    // TODO(beng): this is eff'n weird.
-    new LocalFetcher(
-        network_service_.get(), resolved_url,
-        shell::GetBaseURLAndQuery(resolved_url, nullptr),
-        loader_callback);
-    return;
-  }
-
-#if 0
-  // TODO(beng): figure out how this should be integrated now that mapped_url
-  //             is toast.
-  // TODO(scottmg): to quote someone I know, if you liked this you shouldda put
-  //                a test on it.
-  if (url.SchemeIs("mojo") &&
-      base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kUseUpdater)) {
-    application_manager_->ConnectToService(GURL("mojo:updater"), &updater_);
-    // Ownership of this object is transferred to |loader_callback|.
-    // TODO(beng): this is eff'n weird.
-    new UpdateFetcher(url, updater_.get(), loader_callback);
-    return;
-  }
-#endif
-
-  if (!url_loader_factory_) {
-    application_manager_->ConnectToService(GURL("mojo:network_service"),
-                                           &url_loader_factory_);
-  }
-
-  // Ownership of this object is transferred to |loader_callback|.
-  // TODO(beng): this is eff'n weird.
-  new NetworkFetcher(disable_cache_, request.Pass(), url_loader_factory_.get(),
-                     loader_callback);
-}
-
-}  // namespace fetcher
-}  // namespace mojo
diff --git a/mojo/fetcher/base_application_fetcher.h b/mojo/fetcher/base_application_fetcher.h
deleted file mode 100644
index 5e39f29..0000000
--- a/mojo/fetcher/base_application_fetcher.h
+++ /dev/null
@@ -1,41 +0,0 @@
-// 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/files/file_path.h"
-#include "mojo/fetcher/url_resolver.h"
-#include "mojo/services/network/public/interfaces/network_service.mojom.h"
-#include "mojo/services/network/public/interfaces/url_loader_factory.mojom.h"
-#include "mojo/shell/application_fetcher.h"
-
-namespace mojo {
-namespace fetcher {
-
-// This is the default implementation of shell::ApplicationFetcher. It loads
-// http/s urls off the network as well as providing special handling for mojo:
-// and about: urls.
-class BaseApplicationFetcher : public shell::ApplicationFetcher {
- public:
-  // mojo: urls are only supported if |shell_file_root| is non-empty.
-  BaseApplicationFetcher(const base::FilePath& shell_file_root);
-  ~BaseApplicationFetcher() override;
-
- private:
-  // Overridden from shell::ApplicationFetcher:
-  void SetApplicationManager(shell::ApplicationManager* manager) override;
-  GURL ResolveURL(const GURL& url) override;
-  void FetchRequest(
-      URLRequestPtr request,
-      const shell::Fetcher::FetchCallback& loader_callback) override;
-
-  shell::ApplicationManager* application_manager_;
-  scoped_ptr<URLResolver> url_resolver_;
-  const bool disable_cache_;
-  NetworkServicePtr network_service_;
-  URLLoaderFactoryPtr url_loader_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(BaseApplicationFetcher);
-};
-
-}  // namespace fetcher
-}  // namespace mojo
diff --git a/mojo/mojo_shell.gyp b/mojo/mojo_shell.gyp
index 598ef3d..62bba84 100644
--- a/mojo/mojo_shell.gyp
+++ b/mojo/mojo_shell.gyp
@@ -25,6 +25,7 @@
       'shell/identity.cc',
       'shell/identity.h',
       'shell/native_runner.h',
+      'shell/package_manager.h',
       'shell/query_util.cc',
       'shell/query_util.h',
       'shell/static_application_loader.cc',
@@ -50,8 +51,6 @@
     'sources': [
       'fetcher/about_fetcher.cc',
       'fetcher/about_fetcher.h',
-      'fetcher/base_application_fetcher.cc',
-      'fetcher/base_application_fetcher.h',
       'fetcher/local_fetcher.cc',
       'fetcher/local_fetcher.h',
       'fetcher/network_fetcher.cc',
@@ -62,6 +61,8 @@
       'fetcher/update_fetcher.h',
       'fetcher/url_resolver.cc',
       'fetcher/url_resolver.h',
+      'package_manager/package_manager_impl.cc',
+      'package_manager/package_manager_impl.h',
     ],
     'dependencies': [
       '<(DEPTH)/base/base.gyp:base',
@@ -84,6 +85,8 @@
       'shell/application_manager_unittest.cc',
       'shell/capability_filter_unittest.cc',
       'shell/query_util_unittest.cc',
+      'shell/test_package_manager.cc',
+      'shell/test_package_manager.h',
     ],
     'dependencies': [
       '<(DEPTH)/mojo/mojo_shell.gyp:mojo_shell_lib',
diff --git a/mojo/package_manager/BUILD.gn b/mojo/package_manager/BUILD.gn
new file mode 100644
index 0000000..913a36d
--- /dev/null
+++ b/mojo/package_manager/BUILD.gn
@@ -0,0 +1,16 @@
+# 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.
+
+source_set("package_manager") {
+  sources = [
+    "package_manager_impl.cc",
+    "package_manager_impl.h",
+  ]
+
+  deps = [
+    "//mojo/fetcher",
+    "//mojo/shell",
+    "//mojo/util:filename_util",
+  ]
+}
diff --git a/mojo/package_manager/DEPS b/mojo/package_manager/DEPS
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/mojo/package_manager/DEPS
diff --git a/mojo/package_manager/package_manager_impl.cc b/mojo/package_manager/package_manager_impl.cc
new file mode 100644
index 0000000..f1a1fc6
--- /dev/null
+++ b/mojo/package_manager/package_manager_impl.cc
@@ -0,0 +1,172 @@
+// 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 "mojo/package_manager/package_manager_impl.h"
+
+#include "mojo/fetcher/about_fetcher.h"
+#include "mojo/fetcher/local_fetcher.h"
+#include "mojo/fetcher/network_fetcher.h"
+#include "mojo/fetcher/switches.h"
+#include "mojo/fetcher/update_fetcher.h"
+#include "mojo/shell/application_manager.h"
+#include "mojo/shell/query_util.h"
+#include "mojo/shell/switches.h"
+#include "mojo/util/filename_util.h"
+#include "url/gurl.h"
+
+namespace mojo {
+namespace package_manager {
+
+PackageManagerImpl::PackageManagerImpl(
+    const base::FilePath& shell_file_root)
+    : application_manager_(nullptr),
+      disable_cache_(base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableCache)) {
+  if (!shell_file_root.empty()) {
+    GURL mojo_root_file_url =
+        util::FilePathToFileURL(shell_file_root).Resolve(std::string());
+    url_resolver_.reset(new fetcher::URLResolver(mojo_root_file_url));
+  }
+}
+
+PackageManagerImpl::~PackageManagerImpl() {
+}
+
+void PackageManagerImpl::RegisterContentHandler(
+    const std::string& mime_type,
+    const GURL& content_handler_url) {
+  DCHECK(content_handler_url.is_valid())
+      << "Content handler URL is invalid for mime type " << mime_type;
+  mime_type_to_url_[mime_type] = content_handler_url;
+}
+
+void PackageManagerImpl::RegisterApplicationPackageAlias(
+    const GURL& alias,
+    const GURL& content_handler_package,
+    const std::string& qualifier) {
+  application_package_alias_[alias] =
+      std::make_pair(content_handler_package, qualifier);
+}
+
+void PackageManagerImpl::SetApplicationManager(
+    shell::ApplicationManager* manager) {
+  application_manager_ = manager;
+}
+
+GURL PackageManagerImpl::ResolveURL(const GURL& url) {
+  return url_resolver_.get() ? url_resolver_->ResolveMojoURL(url) : url;
+}
+
+void PackageManagerImpl::FetchRequest(
+    URLRequestPtr request,
+    const shell::Fetcher::FetchCallback& loader_callback) {
+  GURL url(request->url);
+  if (url.SchemeIs(fetcher::AboutFetcher::kAboutScheme)) {
+    fetcher::AboutFetcher::Start(url, loader_callback);
+    return;
+  }
+
+  GURL resolved_url = ResolveURL(url);
+
+  if (resolved_url.SchemeIsFile()) {
+    // LocalFetcher uses the network service to infer MIME types from URLs.
+    // Skip this for mojo URLs to avoid recursively loading the network service.
+    if (!network_service_ && !url.SchemeIs("mojo")) {
+      application_manager_->ConnectToService(GURL("mojo:network_service"),
+                                            &network_service_);
+    }
+    // Ownership of this object is transferred to |loader_callback|.
+    // TODO(beng): this is eff'n weird.
+    new fetcher::LocalFetcher(
+        network_service_.get(), resolved_url,
+        shell::GetBaseURLAndQuery(resolved_url, nullptr),
+        loader_callback);
+    return;
+  }
+
+#if 0
+  // TODO(beng): figure out how this should be integrated now that mapped_url
+  //             is toast.
+  // TODO(scottmg): to quote someone I know, if you liked this you shouldda put
+  //                a test on it.
+  if (url.SchemeIs("mojo") &&
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kUseUpdater)) {
+    application_manager_->ConnectToService(GURL("mojo:updater"), &updater_);
+    // Ownership of this object is transferred to |loader_callback|.
+    // TODO(beng): this is eff'n weird.
+    new fetcher::UpdateFetcher(url, updater_.get(), loader_callback);
+    return;
+  }
+#endif
+
+  if (!url_loader_factory_) {
+    application_manager_->ConnectToService(GURL("mojo:network_service"),
+                                           &url_loader_factory_);
+  }
+
+  // Ownership of this object is transferred to |loader_callback|.
+  // TODO(beng): this is eff'n weird.
+  new fetcher::NetworkFetcher(disable_cache_, request.Pass(),
+                              url_loader_factory_.get(), loader_callback);
+}
+
+bool PackageManagerImpl::HandleWithContentHandler(shell::Fetcher* fetcher,
+                                                  const GURL& unresolved_url,
+                                                  base::TaskRunner* task_runner,
+                                                  URLResponsePtr* new_response,
+                                                  GURL* content_handler_url,
+                                                  std::string* qualifier) {
+  // TODO(beng): it seems like some delegate should/would want to have a say in
+  //             configuring the qualifier also.
+  bool enable_multi_process = base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableMultiprocess);
+
+  // The response begins with a #!mojo <content-handler-url>.
+  std::string shebang;
+  if (fetcher->PeekContentHandler(&shebang, content_handler_url)) {
+    *new_response = fetcher->AsURLResponse(
+        task_runner, static_cast<int>(shebang.size()));
+    *qualifier = enable_multi_process ? (*new_response)->site.To<std::string>()
+                                      : std::string();
+    return true;
+  }
+
+  // The response MIME type matches a registered content handler.
+  MimeTypeToURLMap::iterator iter = mime_type_to_url_.find(fetcher->MimeType());
+  if (iter != mime_type_to_url_.end()) {
+    *new_response = fetcher->AsURLResponse(task_runner, 0);
+    *content_handler_url = iter->second;
+    *qualifier = enable_multi_process ? (*new_response)->site.To<std::string>()
+                                      : std::string();
+    return true;
+  }
+
+  // The response URL matches a registered content handler.
+  auto alias_iter = application_package_alias_.find(unresolved_url);
+  if (alias_iter != application_package_alias_.end()) {
+    // We replace the qualifier with the one our package alias requested.
+    *new_response = URLResponse::New();
+    (*new_response)->url = unresolved_url.spec();
+
+    // Why can't we use this in single process mode? Because of
+    // base::AtExitManager. If you link in ApplicationRunner into your code, and
+    // then we make initialize multiple copies of the application, we end up
+    // with multiple AtExitManagers and will check on the second one being
+    // created.
+    //
+    // Why doesn't that happen when running different apps? Because
+    // your_thing.mojo!base::AtExitManager and
+    // my_thing.mojo!base::AtExitManager are different symbols.
+    *qualifier = enable_multi_process ? alias_iter->second.second
+                                      : std::string();
+    *content_handler_url = alias_iter->second.first;
+    return true;
+  }
+
+  return false;
+}
+
+}  // namespace package_manager
+}  // namespace mojo
diff --git a/mojo/package_manager/package_manager_impl.h b/mojo/package_manager/package_manager_impl.h
new file mode 100644
index 0000000..56961be4
--- /dev/null
+++ b/mojo/package_manager/package_manager_impl.h
@@ -0,0 +1,76 @@
+// 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 MOJO_PACKAGE_MANAGER_PACKAGE_MANAGER_IMPL_H_
+#define MOJO_PACKAGE_MANAGER_PACKAGE_MANAGER_IMPL_H_
+
+#include "base/files/file_path.h"
+#include "mojo/fetcher/url_resolver.h"
+#include "mojo/services/network/public/interfaces/network_service.mojom.h"
+#include "mojo/services/network/public/interfaces/url_loader_factory.mojom.h"
+#include "mojo/shell/package_manager.h"
+
+namespace mojo {
+namespace shell {
+class Fetcher;
+}
+namespace package_manager {
+
+// This is the default implementation of shell::PackageManager. It loads
+// http/s urls off the network as well as providing special handling for mojo:
+// and about: urls.
+class PackageManagerImpl : public shell::PackageManager {
+ public:
+  // mojo: urls are only supported if |shell_file_root| is non-empty.
+  explicit PackageManagerImpl(const base::FilePath& shell_file_root);
+  ~PackageManagerImpl() override;
+
+  // Register a content handler to handle content of |mime_type|.
+  void RegisterContentHandler(const std::string& mime_type,
+                              const GURL& content_handler_url);
+
+  // Registers a package alias. When attempting to load |alias|, it will
+  // instead redirect to |content_handler_package|, which is a content handler
+  // which will be passed the |alias| as the URLResponse::url. Different values
+  // of |alias| with the same |qualifier| that are in the same
+  // |content_handler_package| will run in the same process in multi-process
+  // mode.
+  void RegisterApplicationPackageAlias(
+      const GURL& alias,
+      const GURL& content_handler_package,
+      const std::string& qualifier);
+
+ private:
+  using ApplicationPackagedAlias = std::map<GURL, std::pair<GURL, std::string>>;
+  using MimeTypeToURLMap = std::map<std::string, GURL>;
+
+  // Overridden from shell::PackageManager:
+  void SetApplicationManager(shell::ApplicationManager* manager) override;
+  GURL ResolveURL(const GURL& url) override;
+  void FetchRequest(
+      URLRequestPtr request,
+      const shell::Fetcher::FetchCallback& loader_callback) override;
+  bool HandleWithContentHandler(shell::Fetcher* fetcher,
+                                const GURL& unresolved_url,
+                                base::TaskRunner* task_runner,
+                                URLResponsePtr* new_response,
+                                GURL* content_handler_url,
+                                std::string* qualifier) override;
+
+
+  shell::ApplicationManager* application_manager_;
+  scoped_ptr<fetcher::URLResolver> url_resolver_;
+  const bool disable_cache_;
+  NetworkServicePtr network_service_;
+  URLLoaderFactoryPtr url_loader_factory_;
+  ApplicationPackagedAlias application_package_alias_;
+  MimeTypeToURLMap mime_type_to_url_;
+
+  DISALLOW_COPY_AND_ASSIGN(PackageManagerImpl);
+};
+
+}  // namespace package_manager
+}  // namespace mojo
+
+#endif  // MOJO_PACKAGE_MANAGER_PACKAGE_MANAGER_IMPL_H_
diff --git a/mojo/runner/BUILD.gn b/mojo/runner/BUILD.gn
index f58a23f..5488248 100644
--- a/mojo/runner/BUILD.gn
+++ b/mojo/runner/BUILD.gn
@@ -123,8 +123,8 @@ source_set("lib") {
     "//components/devtools_service/public/interfaces",
     "//mojo/application/public/cpp",
     "//mojo/common:tracing_impl",
-    "//mojo/fetcher",
     "//mojo/message_pump",
+    "//mojo/package_manager",
     "//mojo/services/network/public/interfaces",
     "//mojo/services/tracing/public/cpp",
     "//mojo/services/tracing/public/interfaces",
@@ -441,6 +441,7 @@ test("mojo_runner_unittests") {
     "//mojo/environment:chromium",
     "//mojo/fetcher",
     "//mojo/message_pump",
+    "//mojo/package_manager",
     "//mojo/services/test_service:bindings",
     "//mojo/shell",
     "//mojo/util:filename_util",
diff --git a/mojo/runner/context.cc b/mojo/runner/context.cc
index fc312bf..a1e5989 100644
--- a/mojo/runner/context.cc
+++ b/mojo/runner/context.cc
@@ -29,7 +29,7 @@
 #include "mojo/common/tracing_impl.h"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/edk/embedder/simple_platform_support.h"
-#include "mojo/fetcher/base_application_fetcher.h"
+#include "mojo/package_manager/package_manager_impl.h"
 #include "mojo/runner/in_process_native_runner.h"
 #include "mojo/runner/out_of_process_native_runner.h"
 #include "mojo/runner/switches.h"
@@ -59,7 +59,7 @@ class Setup {
   DISALLOW_COPY_AND_ASSIGN(Setup);
 };
 
-void InitContentHandlers(shell::ApplicationManager* manager,
+void InitContentHandlers(package_manager::PackageManagerImpl* manager,
                          const base::CommandLine& command_line) {
   // Default content handlers.
   manager->RegisterContentHandler("application/pdf", GURL("mojo:pdf_viewer"));
@@ -162,9 +162,7 @@ class TracingServiceProvider : public ServiceProvider {
 }  // namespace
 
 Context::Context(const base::FilePath& shell_file_root)
-    : application_manager_(new shell::ApplicationManager(make_scoped_ptr(
-          new fetcher::BaseApplicationFetcher(shell_file_root)))),
-      main_entry_time_(base::Time::Now()) {}
+    : shell_file_root_(shell_file_root), main_entry_time_(base::Time::Now()) {}
 
 Context::~Context() {
   DCHECK(!base::MessageLoop::current());
@@ -190,6 +188,12 @@ bool Context::Init() {
       embedder::ProcessType::NONE, task_runners_->shell_runner(), this,
       task_runners_->io_runner(), embedder::ScopedPlatformHandle());
 
+  package_manager_ = new package_manager::PackageManagerImpl(shell_file_root_);
+  InitContentHandlers(package_manager_, command_line);
+
+  application_manager_.reset(
+      new shell::ApplicationManager(make_scoped_ptr(package_manager_)));
+
   scoped_ptr<shell::NativeRunnerFactory> runner_factory;
   if (command_line.HasSwitch(switches::kEnableMultiprocess))
     runner_factory.reset(new OutOfProcessNativeRunnerFactory(this));
@@ -198,8 +202,6 @@ bool Context::Init() {
   application_manager_->set_blocking_pool(task_runners_->blocking_pool());
   application_manager_->set_native_runner_factory(runner_factory.Pass());
 
-  InitContentHandlers(application_manager_.get(), command_line);
-
   ServiceProviderPtr service_provider_ptr;
   ServiceProviderPtr tracing_service_provider_ptr;
   new TracingServiceProvider(GetProxy(&tracing_service_provider_ptr));
diff --git a/mojo/runner/context.h b/mojo/runner/context.h
index 52537666..5667385 100644
--- a/mojo/runner/context.h
+++ b/mojo/runner/context.h
@@ -18,6 +18,9 @@
 #include "url/gurl.h"
 
 namespace mojo {
+namespace package_manager {
+class PackageManagerImpl;
+}
 namespace runner {
 
 class NativeApplicationLoader;
@@ -52,6 +55,10 @@ class Context : public embedder::ProcessDelegate {
     return application_manager_.get();
   }
 
+  package_manager::PackageManagerImpl* package_manager() {
+    return package_manager_;
+  }
+
  private:
   class NativeViewportApplicationLoader;
 
@@ -63,6 +70,9 @@ class Context : public embedder::ProcessDelegate {
   ScopedUserDataDir scoped_user_data_dir;
   std::set<GURL> app_urls_;
   scoped_ptr<TaskRunners> task_runners_;
+  base::FilePath shell_file_root_;
+  // Owned by |application_manager_|.
+  package_manager::PackageManagerImpl* package_manager_;
   scoped_ptr<shell::ApplicationManager> application_manager_;
   base::Closure app_complete_callback_;
   base::Time main_entry_time_;
diff --git a/mojo/runner/native_runner_unittest.cc b/mojo/runner/native_runner_unittest.cc
index 5dba563..bfb77b8 100644
--- a/mojo/runner/native_runner_unittest.cc
+++ b/mojo/runner/native_runner_unittest.cc
@@ -4,7 +4,6 @@
 
 #include "base/files/scoped_temp_dir.h"
 #include "base/path_service.h"
-#include "mojo/fetcher/base_application_fetcher.h"
 #include "mojo/runner/context.h"
 #include "mojo/shell/application_manager.h"
 #include "mojo/util/filename_util.h"
diff --git a/mojo/shell/BUILD.gn b/mojo/shell/BUILD.gn
index 8b98e93..38fca1e 100644
--- a/mojo/shell/BUILD.gn
+++ b/mojo/shell/BUILD.gn
@@ -8,7 +8,6 @@ import("//testing/test.gni")
 source_set("shell") {
   output_name = "mojo_shell"
   sources = [
-    "application_fetcher.h",
     "application_instance.cc",
     "application_instance.h",
     "application_loader.h",
@@ -27,6 +26,7 @@ source_set("shell") {
     "identity.cc",
     "identity.h",
     "native_runner.h",
+    "package_manager.h",
     "query_util.cc",
     "query_util.h",
     "static_application_loader.cc",
@@ -60,6 +60,8 @@ test("mojo_shell_unittests") {
     "application_manager_unittest.cc",
     "capability_filter_unittest.cc",
     "query_util_unittest.cc",
+    "test_package_manager.cc",
+    "test_package_manager.h",
   ]
 
   deps = [
diff --git a/mojo/shell/application_fetcher.h b/mojo/shell/application_fetcher.h
deleted file mode 100644
index 4f88001..0000000
--- a/mojo/shell/application_fetcher.h
+++ /dev/null
@@ -1,43 +0,0 @@
-// 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 MOJO_SHELL_APPLICATION_FETCHER_H_
-#define MOJO_SHELL_APPLICATION_FETCHER_H_
-
-#include "mojo/shell/fetcher.h"
-#include "mojo/services/network/public/interfaces/url_loader.mojom.h"
-
-class GURL;
-
-namespace mojo {
-namespace shell {
-
-class ApplicationManager;
-
-// A class implementing this interface assists Shell::ConnectToApplication in
-// resolving URLs and fetching the applications located therein.
-class ApplicationFetcher {
- public:
-  virtual ~ApplicationFetcher() {}
-
-  // Called once, during initialization, to tell the fetcher about the
-  // associated ApplicationManager.
-  virtual void SetApplicationManager(ApplicationManager* manager) = 0;
-
-  // Resolves |url| to its canonical form. e.g. for mojo: urls, returns a file:
-  // url with a path ending in .mojo.
-  virtual GURL ResolveURL(const GURL& url) = 0;
-
-  // Asks the delegate to fetch the specified url. |url| must be unresolved,
-  // i.e. ResolveURL() above must not have been called on it.
-  // TODO(beng): figure out how not to expose Fetcher at all at this layer.
-  virtual void FetchRequest(
-      URLRequestPtr request,
-      const Fetcher::FetchCallback& loader_callback) = 0;
-};
-
-}  // namespace shell
-}  // namespace mojo
-
-#endif  // MOJO_SHELL_APPLICATION_FETCHER_H_
diff --git a/mojo/shell/application_manager.cc b/mojo/shell/application_manager.cc
index 934ea7d..d520304 100644
--- a/mojo/shell/application_manager.cc
+++ b/mojo/shell/application_manager.cc
@@ -13,10 +13,10 @@
 #include "base/trace_event/trace_event.h"
 #include "mojo/application/public/interfaces/content_handler.mojom.h"
 #include "mojo/public/cpp/bindings/binding.h"
-#include "mojo/shell/application_fetcher.h"
 #include "mojo/shell/application_instance.h"
 #include "mojo/shell/content_handler_connection.h"
 #include "mojo/shell/fetcher.h"
+#include "mojo/shell/package_manager.h"
 #include "mojo/shell/query_util.h"
 #include "mojo/shell/switches.h"
 
@@ -50,11 +50,12 @@ bool ApplicationManager::TestAPI::HasRunningInstanceForURL(
          manager_->identity_to_instance_.end();
 }
 
-ApplicationManager::ApplicationManager(scoped_ptr<ApplicationFetcher> fetcher)
-    : fetcher_(fetcher.Pass()),
+ApplicationManager::ApplicationManager(
+    scoped_ptr<PackageManager> package_manager)
+    : package_manager_(package_manager.Pass()),
       content_handler_id_counter_(0u),
       weak_ptr_factory_(this) {
-  fetcher_->SetApplicationManager(this);
+  package_manager_->SetApplicationManager(this);
 }
 
 ApplicationManager::~ApplicationManager() {
@@ -107,7 +108,7 @@ void ApplicationManager::ConnectToApplication(
   if (ConnectToRunningApplication(&params))
     return;
 
-  GURL resolved_url = fetcher_->ResolveURL(original_url);
+  GURL resolved_url = package_manager_->ResolveURL(original_url);
   params->SetURLInfo(resolved_url);
   if (ConnectToRunningApplication(&params))
     return;
@@ -126,7 +127,7 @@ void ApplicationManager::ConnectToApplication(
   auto callback =
       base::Bind(&ApplicationManager::HandleFetchCallback,
                  weak_ptr_factory_.GetWeakPtr(), base::Passed(&params));
-  fetcher_->FetchRequest(original_url_request.Pass(), callback);
+  package_manager_->FetchRequest(original_url_request.Pass(), callback);
 }
 
 bool ApplicationManager::ConnectToRunningApplication(
@@ -226,85 +227,39 @@ void ApplicationManager::HandleFetchCallback(
   ApplicationInstance* app = nullptr;
   InterfaceRequest<Application> request(RegisterInstance(params.Pass(), &app));
 
-  // For resources that are loaded with content handlers, we group app instances
-  // by site.
 
-  // If the response begins with a #!mojo <content-handler-url>, use it.
   GURL content_handler_url;
-  std::string shebang;
-  // TODO(beng): it seems like some delegate should/would want to have a say in
-  //             configuring the qualifier also.
-  bool enable_multi_process = base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableMultiprocess);
-
-  if (fetcher->PeekContentHandler(&shebang, &content_handler_url)) {
-    URLResponsePtr response(fetcher->AsURLResponse(
-        blocking_pool_, static_cast<int>(shebang.size())));
-    std::string site =
-        enable_multi_process ? response->site.To<std::string>() : std::string();
+  URLResponsePtr new_response;
+  if (package_manager_->HandleWithContentHandler(fetcher.get(),
+                                                 app_url,
+                                                 blocking_pool_,
+                                                 &new_response,
+                                                 &content_handler_url,
+                                                 &qualifier)) {
     LoadWithContentHandler(originator_identity, originator_filter,
-                           content_handler_url, site, filter, connect_callback,
-                           app, request.Pass(), response.Pass());
-    return;
-  }
-
-  MimeTypeToURLMap::iterator iter = mime_type_to_url_.find(fetcher->MimeType());
-  if (iter != mime_type_to_url_.end()) {
-    URLResponsePtr response(fetcher->AsURLResponse(blocking_pool_, 0));
-    std::string site =
-        enable_multi_process ? response->site.To<std::string>() : std::string();
-    LoadWithContentHandler(originator_identity, originator_filter, iter->second,
-                           site, filter, connect_callback, app, request.Pass(),
-                           response.Pass());
-    return;
-  }
-
-  auto alias_iter = application_package_alias_.find(app_url);
-  if (alias_iter != application_package_alias_.end()) {
-    // We replace the qualifier with the one our package alias requested.
-    URLResponsePtr response(URLResponse::New());
-    response->url = app_url.spec();
-
-    std::string qualifier;
-    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kEnableMultiprocess)) {
-      // Why can't we use this in single process mode? Because of
-      // base::AtExitManager. If you link in ApplicationRunner into
-      // your code, and then we make initialize multiple copies of the
-      // application, we end up with multiple AtExitManagers and will check on
-      // the second one being created.
-      //
-      // Why doesn't that happen when running different apps? Because
-      // your_thing.mojo!base::AtExitManager and
-      // my_thing.mojo!base::AtExitManager are different symbols.
-      qualifier = alias_iter->second.second;
+                           content_handler_url, qualifier, filter,
+                           connect_callback, app, request.Pass(),
+                           new_response.Pass());
+  } else {
+    // TODO(erg): Have a better way of switching the sandbox on. For now, switch
+    // it on hard coded when we're using some of the sandboxable core services.
+    bool start_sandboxed = false;
+    if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kMojoNoSandbox)) {
+      if (app_url == GURL("mojo://core_services/") && qualifier == "Core")
+        start_sandboxed = true;
+      else if (app_url == GURL("mojo://html_viewer/"))
+        start_sandboxed = true;
     }
 
-    LoadWithContentHandler(originator_identity, originator_filter,
-                           alias_iter->second.first, qualifier, filter,
-                           connect_callback, app, request.Pass(),
-                           response.Pass());
-    return;
-  }
+    connect_callback.Run(Shell::kInvalidContentHandlerID);
 
-  // TODO(erg): Have a better way of switching the sandbox on. For now, switch
-  // it on hard coded when we're using some of the sandboxable core services.
-  bool start_sandboxed = false;
-  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kMojoNoSandbox)) {
-    if (app_url == GURL("mojo://core_services/") && qualifier == "Core")
-      start_sandboxed = true;
-    else if (app_url == GURL("mojo://html_viewer/"))
-      start_sandboxed = true;
+    fetcher->AsPath(blocking_pool_,
+                    base::Bind(&ApplicationManager::RunNativeApplication,
+                               weak_ptr_factory_.GetWeakPtr(),
+                               base::Passed(request.Pass()), start_sandboxed,
+                               base::Passed(fetcher.Pass())));
   }
-
-  connect_callback.Run(Shell::kInvalidContentHandlerID);
-
-  fetcher->AsPath(blocking_pool_,
-                  base::Bind(&ApplicationManager::RunNativeApplication,
-                             weak_ptr_factory_.GetWeakPtr(),
-                             base::Passed(request.Pass()), start_sandboxed,
-                             base::Passed(fetcher.Pass())));
 }
 
 void ApplicationManager::RunNativeApplication(
@@ -333,22 +288,6 @@ void ApplicationManager::RunNativeApplication(
                            weak_ptr_factory_.GetWeakPtr(), runner));
 }
 
-void ApplicationManager::RegisterContentHandler(
-    const std::string& mime_type,
-    const GURL& content_handler_url) {
-  DCHECK(content_handler_url.is_valid())
-      << "Content handler URL is invalid for mime type " << mime_type;
-  mime_type_to_url_[mime_type] = content_handler_url;
-}
-
-void ApplicationManager::RegisterApplicationPackageAlias(
-    const GURL& alias,
-    const GURL& content_handler_package,
-    const std::string& qualifier) {
-  application_package_alias_[alias] =
-      std::make_pair(content_handler_package, qualifier);
-}
-
 void ApplicationManager::LoadWithContentHandler(
     const Identity& originator_identity,
     const CapabilityFilter& originator_filter,
diff --git a/mojo/shell/application_manager.h b/mojo/shell/application_manager.h
index b0c742f..0ec2a6e 100644
--- a/mojo/shell/application_manager.h
+++ b/mojo/shell/application_manager.h
@@ -33,7 +33,7 @@ class SequencedWorkerPool;
 namespace mojo {
 namespace shell {
 
-class ApplicationFetcher;
+class PackageManager;
 class ApplicationInstance;
 class ContentHandlerConnection;
 
@@ -55,7 +55,7 @@ class ApplicationManager {
     DISALLOW_COPY_AND_ASSIGN(TestAPI);
   };
 
-  explicit ApplicationManager(scoped_ptr<ApplicationFetcher> fetcher);
+  explicit ApplicationManager(scoped_ptr<PackageManager> package_manager);
   ~ApplicationManager();
 
   // Loads a service if necessary and establishes a new client connection.
@@ -86,19 +86,6 @@ class ApplicationManager {
     ptr->Bind(InterfacePtrInfo<Interface>(service_handle.Pass(), 0u));
   }
 
-  void RegisterContentHandler(const std::string& mime_type,
-                              const GURL& content_handler_url);
-
-  // Registers a package alias. When attempting to load |alias|, it will
-  // instead redirect to |content_handler_package|, which is a content handler
-  // which will be passed the |alias| as the URLResponse::url. Different values
-  // of |alias| with the same |qualifier| that are in the same
-  // |content_handler_package| will run in the same process in multi-process
-  // mode.
-  void RegisterApplicationPackageAlias(const GURL& alias,
-                                       const GURL& content_handler_package,
-                                       const std::string& qualifier);
-
   // Sets the default Loader to be used if not overridden by SetLoaderForURL().
   void set_default_loader(scoped_ptr<ApplicationLoader> loader) {
     default_loader_ = loader.Pass();
@@ -128,10 +115,8 @@ class ApplicationManager {
   ApplicationInstance* GetApplicationInstance(const Identity& identity) const;
 
  private:
-  using ApplicationPackagedAlias = std::map<GURL, std::pair<GURL, std::string>>;
   using IdentityToApplicationInstanceMap =
       std::map<Identity, ApplicationInstance*>;
-  using MimeTypeToURLMap = std::map<std::string, GURL>;
   using URLToContentHandlerMap =
       std::map<std::pair<GURL, std::string>, ContentHandlerConnection*>;
   using URLToLoaderMap = std::map<GURL, ApplicationLoader*>;
@@ -185,20 +170,18 @@ class ApplicationManager {
       const GURL& application_url,
       const std::string& interface_name);
 
-  scoped_ptr<ApplicationFetcher> const fetcher_;
+  scoped_ptr<PackageManager> const package_manager_;
   // Loader management.
   // Loaders are chosen in the order they are listed here.
   URLToLoaderMap url_to_loader_;
   scoped_ptr<ApplicationLoader> default_loader_;
   scoped_ptr<NativeRunnerFactory> native_runner_factory_;
 
-  ApplicationPackagedAlias application_package_alias_;
   IdentityToApplicationInstanceMap identity_to_instance_;
   URLToContentHandlerMap url_to_content_handler_;
 
   base::SequencedWorkerPool* blocking_pool_;
   updater::UpdaterPtr updater_;
-  MimeTypeToURLMap mime_type_to_url_;
   ScopedVector<NativeRunner> native_runners_;
   // Counter used to assign ids to content_handlers.
   uint32_t content_handler_id_counter_;
diff --git a/mojo/shell/application_manager_unittest.cc b/mojo/shell/application_manager_unittest.cc
index 644c965..77a959c 100644
--- a/mojo/shell/application_manager_unittest.cc
+++ b/mojo/shell/application_manager_unittest.cc
@@ -15,11 +15,11 @@
 #include "mojo/application/public/interfaces/content_handler.mojom.h"
 #include "mojo/application/public/interfaces/service_provider.mojom.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
-#include "mojo/shell/application_fetcher.h"
 #include "mojo/shell/application_loader.h"
 #include "mojo/shell/application_manager.h"
 #include "mojo/shell/fetcher.h"
 #include "mojo/shell/test.mojom.h"
+#include "mojo/shell/test_package_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
@@ -456,13 +456,13 @@ class Tester : public ApplicationDelegate,
   ScopedVector<TestAImpl> a_bindings_;
 };
 
-class TestApplicationFetcher : public ApplicationFetcher {
+class AMTestPackageManager : public TestPackageManager {
  public:
-  TestApplicationFetcher()
+   AMTestPackageManager()
       : create_test_fetcher_(false),
         fetcher_url_("xxx"),
         mime_type_(kTestMimeType) {}
-  ~TestApplicationFetcher() override {}
+   ~AMTestPackageManager() override {}
 
   void set_create_test_fetcher(bool create_test_fetcher) {
     create_test_fetcher_ = create_test_fetcher;
@@ -472,8 +472,7 @@ class TestApplicationFetcher : public ApplicationFetcher {
 
   void set_mime_type(const std::string& mime_type) { mime_type_ = mime_type; }
 
-  // ApplicationManager::Delegate
-  void SetApplicationManager(ApplicationManager* manager) override {}
+  // TestPackageManager:
   GURL ResolveURL(const GURL& url) override {
     GURL resolved_url = url;
     // The shell automatically map mojo URLs.
@@ -495,7 +494,7 @@ class TestApplicationFetcher : public ApplicationFetcher {
   GURL fetcher_url_;
   std::string mime_type_;
 
-  DISALLOW_COPY_AND_ASSIGN(TestApplicationFetcher);
+  DISALLOW_COPY_AND_ASSIGN(AMTestPackageManager);
 };
 
 class ApplicationManagerTest : public testing::Test {
@@ -506,7 +505,7 @@ class ApplicationManagerTest : public testing::Test {
 
   void SetUp() override {
     application_manager_.reset(new ApplicationManager(
-        make_scoped_ptr(new TestApplicationFetcher)));
+        make_scoped_ptr(new AMTestPackageManager)));
     test_loader_ = new TestApplicationLoader;
     test_loader_->set_context(&context_);
     application_manager_->set_default_loader(
@@ -563,7 +562,7 @@ TEST_F(ApplicationManagerTest, ClientError) {
 
 TEST_F(ApplicationManagerTest, Deletes) {
   {
-    ApplicationManager am(make_scoped_ptr(new TestApplicationFetcher));
+    ApplicationManager am(make_scoped_ptr(new AMTestPackageManager));
     TestApplicationLoader* default_loader = new TestApplicationLoader;
     default_loader->set_context(&context_);
     TestApplicationLoader* url_loader1 = new TestApplicationLoader;
@@ -709,13 +708,13 @@ TEST(ApplicationManagerTest2, ContentHandlerConnectionGetsRequestorURL) {
   const GURL requestor_url("http://requestor.url");
   TestContext test_context;
   base::MessageLoop loop;
-  scoped_ptr<TestApplicationFetcher> test_application_fetcher(
-      new TestApplicationFetcher);
-  test_application_fetcher->set_create_test_fetcher(true);
-  ApplicationManager application_manager(test_application_fetcher.Pass());
+  scoped_ptr<AMTestPackageManager> test_package_manager(
+      new AMTestPackageManager);
+  test_package_manager->set_create_test_fetcher(true);
+  test_package_manager->RegisterContentHandler(kTestMimeType,
+                                               content_handler_url);
+  ApplicationManager application_manager(test_package_manager.Pass());
   application_manager.set_default_loader(nullptr);
-  application_manager.RegisterContentHandler(kTestMimeType,
-                                             content_handler_url);
 
   TestApplicationLoader* loader = new TestApplicationLoader;
   loader->set_context(&test_context);
@@ -775,14 +774,14 @@ TEST(ApplicationManagerTest2,
   const GURL content_handler_url("http://test.content.handler");
   const GURL requestor_url("http://requestor.url");
   TestContext test_context;
-  scoped_ptr<TestApplicationFetcher> test_application_fetcher(
-      new TestApplicationFetcher);
-  test_application_fetcher->set_fetcher_url(GURL("test:test"));
-  test_application_fetcher->set_create_test_fetcher(true);
-  ApplicationManager application_manager(test_application_fetcher.Pass());
+  scoped_ptr<AMTestPackageManager> test_package_manager(
+      new AMTestPackageManager);
+  test_package_manager->set_fetcher_url(GURL("test:test"));
+  test_package_manager->set_create_test_fetcher(true);
+  test_package_manager->RegisterContentHandler(kTestMimeType,
+                                               content_handler_url);
+  ApplicationManager application_manager(test_package_manager.Pass());
   application_manager.set_default_loader(nullptr);
-  application_manager.RegisterContentHandler(kTestMimeType,
-                                             content_handler_url);
 
   TestApplicationLoader* content_handler_loader = new TestApplicationLoader;
   content_handler_loader->set_create_content_handler(true);
@@ -834,14 +833,13 @@ TEST(ApplicationManagerTest2, DifferedContentHandlersGetDifferentIDs) {
   const GURL content_handler_url("http://test.content.handler");
   const GURL requestor_url("http://requestor.url");
   TestContext test_context;
-  TestApplicationFetcher* test_application_fetcher = new TestApplicationFetcher;
-  test_application_fetcher->set_fetcher_url(GURL("test:test"));
-  test_application_fetcher->set_create_test_fetcher(true);
-  ApplicationManager application_manager(
-      make_scoped_ptr(test_application_fetcher));
+  AMTestPackageManager* test_package_manager = new AMTestPackageManager;
+  test_package_manager->set_fetcher_url(GURL("test:test"));
+  test_package_manager->set_create_test_fetcher(true);
+  test_package_manager->RegisterContentHandler(kTestMimeType,
+                                               content_handler_url);
+  ApplicationManager application_manager(make_scoped_ptr(test_package_manager));
   application_manager.set_default_loader(nullptr);
-  application_manager.RegisterContentHandler(kTestMimeType,
-                                             content_handler_url);
 
   TestApplicationLoader* content_handler_loader = new TestApplicationLoader;
   content_handler_loader->set_create_content_handler(true);
@@ -870,9 +868,10 @@ TEST(ApplicationManagerTest2, DifferedContentHandlersGetDifferentIDs) {
 
   const std::string mime_type2("test/mime-type2");
   const GURL content_handler_url2("http://test.content2.handler");
-  test_application_fetcher->set_fetcher_url(GURL("test2:test2"));
-  test_application_fetcher->set_mime_type(mime_type2);
-  application_manager.RegisterContentHandler(mime_type2, content_handler_url2);
+  test_package_manager->set_fetcher_url(GURL("test2:test2"));
+  test_package_manager->set_mime_type(mime_type2);
+  test_package_manager->RegisterContentHandler(mime_type2,
+                                               content_handler_url2);
 
   TestApplicationLoader* content_handler_loader2 = new TestApplicationLoader;
   content_handler_loader->set_create_content_handler(true);
diff --git a/mojo/shell/capability_filter_unittest.cc b/mojo/shell/capability_filter_unittest.cc
index a659d42..0c33a8f 100644
--- a/mojo/shell/capability_filter_unittest.cc
+++ b/mojo/shell/capability_filter_unittest.cc
@@ -18,10 +18,10 @@
 #include "mojo/application/public/interfaces/content_handler.mojom.h"
 #include "mojo/common/weak_binding_set.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
-#include "mojo/shell/application_fetcher.h"
 #include "mojo/shell/application_loader.h"
 #include "mojo/shell/application_manager.h"
 #include "mojo/shell/capability_filter_unittest.mojom.h"
+#include "mojo/shell/test_package_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
@@ -285,21 +285,17 @@ class TestFetcher : public Fetcher {
   DISALLOW_COPY_AND_ASSIGN(TestFetcher);
 };
 
-class TestApplicationFetcher : public ApplicationFetcher {
+class CFTestPackageManager : public TestPackageManager {
  public:
-   TestApplicationFetcher() {}
-   ~TestApplicationFetcher() override {}
+  CFTestPackageManager() {}
+  ~CFTestPackageManager() override {}
 
    void set_use_test_fetcher(bool use_test_fetcher) {
      use_test_fetcher_ = use_test_fetcher;
    }
 
  private:
-  // Overridden from ApplicationFetcher:
-  void SetApplicationManager(ApplicationManager* manager) override {}
-  GURL ResolveURL(const GURL& url) override {
-    return url;
-  }
+  // Overridden from TestPackageManager:
   void FetchRequest(URLRequestPtr request,
                     const Fetcher::FetchCallback& loader_callback) override {
     if (use_test_fetcher_)
@@ -308,7 +304,7 @@ class TestApplicationFetcher : public ApplicationFetcher {
 
   bool use_test_fetcher_;
 
-  DISALLOW_COPY_AND_ASSIGN(TestApplicationFetcher);
+  DISALLOW_COPY_AND_ASSIGN(CFTestPackageManager);
 };
 
 class TestLoader : public ApplicationLoader {
@@ -331,7 +327,7 @@ class TestLoader : public ApplicationLoader {
 class CapabilityFilterTest : public testing::Test {
  public:
    CapabilityFilterTest()
-      : test_application_fetcher_(nullptr),
+      : test_package_manager_(nullptr),
         validator_(nullptr) {}
    ~CapabilityFilterTest() override {}
 
@@ -376,7 +372,7 @@ class CapabilityFilterTest : public testing::Test {
     set_use_test_fetcher();
 
     GURL content_handler_url("test:content_handler");
-    application_manager()->RegisterContentHandler(kTestMimeType,
+    test_package_manager_->RegisterContentHandler(kTestMimeType,
                                                   content_handler_url);
 
     CreateLoader<TestContentHandler>(content_handler_url.spec());
@@ -389,20 +385,20 @@ class CapabilityFilterTest : public testing::Test {
   }
   ConnectionValidator* validator() { return validator_; }
   void set_use_test_fetcher() {
-    test_application_fetcher_->set_use_test_fetcher(true);
+    test_package_manager_->set_use_test_fetcher(true);
   }
 
   // Overridden from testing::Test:
   void SetUp() override {
-    test_application_fetcher_ = new TestApplicationFetcher;
+    test_package_manager_ = new CFTestPackageManager;
     application_manager_.reset(
-        new ApplicationManager(make_scoped_ptr(test_application_fetcher_)));
+        new ApplicationManager(make_scoped_ptr(test_package_manager_)));
     CreateLoader<ServiceApplication>("test:service");
     CreateLoader<ServiceApplication>("test:service2");
   }
   void TearDown() override {
     application_manager_.reset();
-    test_application_fetcher_->set_use_test_fetcher(false);
+    test_package_manager_->set_use_test_fetcher(false);
   }
 
  private:
@@ -411,7 +407,7 @@ class CapabilityFilterTest : public testing::Test {
     return scoped_ptr<ApplicationDelegate>(new T);
   }
 
-  TestApplicationFetcher* test_application_fetcher_;
+  CFTestPackageManager* test_package_manager_;
   base::ShadowingAtExitManager at_exit_;
   base::MessageLoop loop_;
   scoped_ptr<ApplicationManager> application_manager_;
diff --git a/mojo/shell/package_manager.h b/mojo/shell/package_manager.h
new file mode 100644
index 0000000..ffd84cd
--- /dev/null
+++ b/mojo/shell/package_manager.h
@@ -0,0 +1,62 @@
+// 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 MOJO_SHELL_PACKAGE_MANAGER_H_
+#define MOJO_SHELL_PACKAGE_MANAGER_H_
+
+#include "mojo/services/network/public/interfaces/url_loader.mojom.h"
+#include "mojo/shell/fetcher.h"
+
+class GURL;
+
+namespace mojo {
+namespace shell {
+
+class ApplicationManager;
+
+// A class implementing this interface assists Shell::ConnectToApplication in
+// resolving URLs and fetching the applications located therein.
+class PackageManager {
+ public:
+  PackageManager() {}
+  virtual ~PackageManager() {}
+
+  // Called once, during initialization, to tell the package manager about the
+  // associated ApplicationManager.
+  virtual void SetApplicationManager(ApplicationManager* manager) = 0;
+
+  // Resolves |url| to its canonical form. e.g. for mojo: urls, returns a file:
+  // url with a path ending in .mojo.
+  virtual GURL ResolveURL(const GURL& url) = 0;
+
+  // Asks the delegate to fetch the specified url. |url| must be unresolved,
+  // i.e. ResolveURL() above must not have been called on it.
+  // TODO(beng): figure out how not to expose Fetcher at all at this layer.
+  virtual void FetchRequest(
+      URLRequestPtr request,
+      const Fetcher::FetchCallback& loader_callback) = 0;
+
+  // Determine if a content handler should handle the response received by
+  // |fetcher|.
+  // |unresolved_url| is the url requested initially by a call to
+  // Shell::ConnectToApplication() before any resolution is applied.
+  // |task_runner| is a base::TaskRunner* that can be used to post callbacks.
+  // |new_response| is the response that should be passed to
+  // ContentHandler::StartApplication(), unchanged if the return value is false.
+  // |content_handler_url| is the url of the content handler application to
+  // run, unchanged if the return value is false.
+  // |qualifier| is the Identity qualifier that the content handler application
+  // instance should be associated with, unchanged if the return value is false.
+  virtual bool HandleWithContentHandler(Fetcher* fetcher,
+                                        const GURL& unresolved_url,
+                                        base::TaskRunner* task_runner,
+                                        URLResponsePtr* new_response,
+                                        GURL* content_handler_url,
+                                        std::string* qualifier) = 0;
+};
+
+}  // namespace shell
+}  // namespace mojo
+
+#endif  // MOJO_SHELL_PACKAGE_MANAGER_H_
diff --git a/mojo/shell/test_package_manager.cc b/mojo/shell/test_package_manager.cc
new file mode 100644
index 0000000..726d3c8
--- /dev/null
+++ b/mojo/shell/test_package_manager.cc
@@ -0,0 +1,54 @@
+// 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 "mojo/shell/test_package_manager.h"
+
+#include "base/logging.h"
+#include "mojo/shell/fetcher.h"
+#include "url/gurl.h"
+
+namespace mojo {
+namespace shell {
+
+TestPackageManager::TestPackageManager() {}
+TestPackageManager::~TestPackageManager() {}
+
+void TestPackageManager::RegisterContentHandler(
+    const std::string& mime_type,
+    const GURL& content_handler_url) {
+  DCHECK(content_handler_url.is_valid())
+      << "Content handler URL is invalid for mime type " << mime_type;
+  mime_type_to_url_[mime_type] = content_handler_url;
+}
+
+void TestPackageManager::SetApplicationManager(ApplicationManager* manager) {
+}
+
+GURL TestPackageManager::ResolveURL(const GURL& url) {
+  return url;
+}
+
+void TestPackageManager::FetchRequest(
+    URLRequestPtr request,
+    const Fetcher::FetchCallback& loader_callback) {}
+
+bool TestPackageManager::HandleWithContentHandler(
+    Fetcher* fetcher,
+    const GURL& unresolved_url,
+    base::TaskRunner* task_runner,
+    URLResponsePtr* new_response,
+    GURL* content_handler_url,
+    std::string* qualifier) {
+  MimeTypeToURLMap::iterator iter = mime_type_to_url_.find(fetcher->MimeType());
+  if (iter != mime_type_to_url_.end()) {
+    *new_response = fetcher->AsURLResponse(task_runner, 0);
+    *content_handler_url = iter->second;
+    *qualifier = (*new_response)->site.To<std::string>();
+    return true;
+  }
+  return false;
+}
+
+}  // namespace shell
+}  // namespace mojo
diff --git a/mojo/shell/test_package_manager.h b/mojo/shell/test_package_manager.h
new file mode 100644
index 0000000..6a3e29f
--- /dev/null
+++ b/mojo/shell/test_package_manager.h
@@ -0,0 +1,52 @@
+// 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 MOJO_SHELL_TEST_PACKAGE_MANAGER_H_
+#define MOJO_SHELL_TEST_PACKAGE_MANAGER_H_
+
+#include <map>
+#include <string>
+
+#include "mojo/shell/package_manager.h"
+
+class GURL;
+
+namespace mojo {
+namespace shell {
+
+// An implementation of PackageManager used by tests to support content handler
+// registration for MIME types.
+class TestPackageManager : public PackageManager {
+ public:
+  TestPackageManager();
+  virtual ~TestPackageManager();
+
+  void RegisterContentHandler(const std::string& mime_type,
+                              const GURL& content_handler_url);
+
+ private:
+  using MimeTypeToURLMap = std::map<std::string, GURL>;
+
+  // Overridden from PackageManager:
+  void SetApplicationManager(ApplicationManager* manager) override;
+  GURL ResolveURL(const GURL& url) override;
+  void FetchRequest(
+      URLRequestPtr request,
+      const Fetcher::FetchCallback& loader_callback) override;
+  bool HandleWithContentHandler(Fetcher* fetcher,
+                                const GURL& unresolved_url,
+                                base::TaskRunner* task_runner,
+                                URLResponsePtr* new_response,
+                                GURL* content_handler_url,
+                                std::string* qualifier) override;
+
+  MimeTypeToURLMap mime_type_to_url_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestPackageManager);
+};
+
+}  // namespace shell
+}  // namespace mojo
+
+#endif  // MOJO_SHELL_TEST_PACKAGE_MANAGER_H_