Add extensions code to use common updater in components/update_client/

This is another piece of work towards implementing differential
extensions update and share autoupdate code with the chrome components
system. It adds code to the extensions/browser directory that makes use
of the common autoupdate code via the update_client::UpdateClient class
to send update checks to the server, download a full .crx or
differential update, and hand back an unpacked directory with the
contents of the new extension version.

This CL does not yet add any code in chrome/ that actually uses these
new capabilities; that will be in a forthcoming CL.

BUG=490418

Review URL: https://codereview.chromium.org/1362043005

Cr-Commit-Position: refs/heads/master@{#354370}

27 files changed, 759 insertions, 333 deletions

diff --git a/extensions/browser/BUILD.gn b/extensions/browser/BUILD.gn
index 9c9424e..3fe0d25 100644
--- a/extensions/browser/BUILD.gn
+++ b/extensions/browser/BUILD.gn
@@ -18,6 +18,8 @@ source_set("browser") {
     "//components/pref_registry",
     "//components/sessions",
     "//components/ui/zoom",
+    "//components/update_client",
+    "//components/version_info",
     "//components/web_cache/browser",
     "//components/web_modal",
     "//content/public/browser",
diff --git a/extensions/browser/extension_system.h b/extensions/browser/extension_system.h
index c6d2e09..7758051d 100644
--- a/extensions/browser/extension_system.h
+++ b/extensions/browser/extension_system.h
@@ -122,6 +122,13 @@ class ExtensionSystem : public KeyedService {
   // so it can be retrieved from ExtensionSystem directly.
   virtual scoped_ptr<ExtensionSet> GetDependentExtensions(
       const Extension* extension) = 0;
+
+  // Install an updated version of |extension_id| with the version given in
+  // temp_dir. Ownership of |temp_dir| in the filesystem is transferred and
+  // implementors of this function are responsible for cleaning it up on
+  // errors, etc.
+  virtual void InstallUpdate(const std::string& extension_id,
+                             const base::FilePath& temp_dir) = 0;
 };
 
 }  // namespace extensions
diff --git a/extensions/browser/extensions_browser_client.cc b/extensions/browser/extensions_browser_client.cc
index 495ac50..d113f11 100644
--- a/extensions/browser/extensions_browser_client.cc
+++ b/extensions/browser/extensions_browser_client.cc
@@ -6,7 +6,9 @@
 
 #include "base/basictypes.h"
 #include "base/logging.h"
+#include "components/update_client/update_client.h"
 #include "extensions/browser/extension_error.h"
+#include "extensions/browser/updater/update_client_config.h"
 
 namespace extensions {
 
@@ -16,6 +18,11 @@ ExtensionsBrowserClient* g_client = NULL;
 
 }  // namespace
 
+scoped_refptr<update_client::UpdateClient>
+ExtensionsBrowserClient::CreateUpdateClient(content::BrowserContext* context) {
+  return scoped_refptr<update_client::UpdateClient>(nullptr);
+}
+
 void ExtensionsBrowserClient::ReportError(content::BrowserContext* context,
                                           scoped_ptr<ExtensionError> error) {
   LOG(ERROR) << error->GetDebugString();
diff --git a/extensions/browser/extensions_browser_client.h b/extensions/browser/extensions_browser_client.h
index 89763d9..a5ddd86 100644
--- a/extensions/browser/extensions_browser_client.h
+++ b/extensions/browser/extensions_browser_client.h
@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>
 
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "extensions/browser/extension_event_histogram_value.h"
 #include "extensions/browser/extension_prefs_observer.h"
@@ -35,6 +36,10 @@ class URLRequest;
 class URLRequestJob;
 }
 
+namespace update_client {
+class UpdateClient;
+}
+
 namespace extensions {
 
 class ApiActivityMonitor;
@@ -236,6 +241,10 @@ class ExtensionsBrowserClient {
   virtual void AttachExtensionTaskManagerTag(content::WebContents* web_contents,
                                              ViewType view_type) {}
 
+  // Returns a new UpdateClient.
+  virtual scoped_refptr<update_client::UpdateClient> CreateUpdateClient(
+      content::BrowserContext* context);
+
   // Returns the single instance of |this|.
   static ExtensionsBrowserClient* Get();
 
diff --git a/extensions/browser/mock_extension_system.cc b/extensions/browser/mock_extension_system.cc
index 00e3fc2..efcc546 100644
--- a/extensions/browser/mock_extension_system.cc
+++ b/extensions/browser/mock_extension_system.cc
@@ -71,4 +71,9 @@ scoped_ptr<ExtensionSet> MockExtensionSystem::GetDependentExtensions(
   return scoped_ptr<ExtensionSet>();
 }
 
+void MockExtensionSystem::InstallUpdate(const std::string& extension_id,
+                                        const base::FilePath& temp_dir) {
+  NOTREACHED();
+}
+
 }  // namespace extensions
diff --git a/extensions/browser/mock_extension_system.h b/extensions/browser/mock_extension_system.h
index af847f5..b055b42 100644
--- a/extensions/browser/mock_extension_system.h
+++ b/extensions/browser/mock_extension_system.h
@@ -41,6 +41,8 @@ class MockExtensionSystem : public ExtensionSystem {
   ContentVerifier* content_verifier() override;
   scoped_ptr<ExtensionSet> GetDependentExtensions(
       const Extension* extension) override;
+  void InstallUpdate(const std::string& extension_id,
+                     const base::FilePath& temp_dir) override;
 
  private:
   content::BrowserContext* browser_context_;
diff --git a/extensions/browser/test_extensions_browser_client.cc b/extensions/browser/test_extensions_browser_client.cc
index d98f7af..da5ef27 100644
--- a/extensions/browser/test_extensions_browser_client.cc
+++ b/extensions/browser/test_extensions_browser_client.cc
@@ -27,6 +27,11 @@ TestExtensionsBrowserClient::TestExtensionsBrowserClient(
 
 TestExtensionsBrowserClient::~TestExtensionsBrowserClient() {}
 
+void TestExtensionsBrowserClient::SetUpdateClientFactory(
+    const base::Callback<update_client::UpdateClient*(void)>& factory) {
+  update_client_factory_ = factory;
+}
+
 void TestExtensionsBrowserClient::SetIncognitoContext(BrowserContext* context) {
   // If a context is provided it must be off-the-record.
   DCHECK(!context || context->IsOffTheRecord());
@@ -204,4 +209,12 @@ TestExtensionsBrowserClient::GetExtensionWebContentsObserver(
   return nullptr;
 }
 
+scoped_refptr<update_client::UpdateClient>
+TestExtensionsBrowserClient::CreateUpdateClient(
+    content::BrowserContext* context) {
+  return update_client_factory_.is_null()
+             ? nullptr
+             : make_scoped_refptr(update_client_factory_.Run());
+}
+
 }  // namespace extensions
diff --git a/extensions/browser/test_extensions_browser_client.h b/extensions/browser/test_extensions_browser_client.h
index 274a8a9..be660e7 100644
--- a/extensions/browser/test_extensions_browser_client.h
+++ b/extensions/browser/test_extensions_browser_client.h
@@ -5,7 +5,13 @@
 #ifndef EXTENSIONS_BROWSER_TEST_EXTENSIONS_BROWSER_CLIENT_H_
 #define EXTENSIONS_BROWSER_TEST_EXTENSIONS_BROWSER_CLIENT_H_
 
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
 #include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "components/update_client/update_client.h"
 #include "extensions/browser/extensions_browser_client.h"
 #include "extensions/browser/updater/extension_cache.h"
 
@@ -30,6 +36,10 @@ class TestExtensionsBrowserClient : public ExtensionsBrowserClient {
     extension_cache_ = extension_cache.Pass();
   }
 
+  // Sets a factory to respond to calls of the CreateUpdateClient method.
+  void SetUpdateClientFactory(
+      const base::Callback<update_client::UpdateClient*(void)>& factory);
+
   // Associates an incognito context with |main_context_|.
   void SetIncognitoContext(content::BrowserContext* incognito_context);
 
@@ -97,6 +107,8 @@ class TestExtensionsBrowserClient : public ExtensionsBrowserClient {
   bool IsMinBrowserVersionSupported(const std::string& min_version) override;
   ExtensionWebContentsObserver* GetExtensionWebContentsObserver(
       content::WebContents* web_contents) override;
+  scoped_refptr<update_client::UpdateClient> CreateUpdateClient(
+      content::BrowserContext* context) override;
 
  private:
   content::BrowserContext* main_context_;       // Not owned.
@@ -110,6 +122,8 @@ class TestExtensionsBrowserClient : public ExtensionsBrowserClient {
 
   scoped_ptr<ExtensionCache> extension_cache_;
 
+  base::Callback<update_client::UpdateClient*(void)> update_client_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(TestExtensionsBrowserClient);
 };
 
diff --git a/extensions/browser/updater/update_client_config.cc b/extensions/browser/updater/update_client_config.cc
new file mode 100644
index 0000000..9f1d0d1
--- /dev/null
+++ b/extensions/browser/updater/update_client_config.cc
@@ -0,0 +1,29 @@
+// 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 "extensions/browser/updater/update_client_config.h"
+
+#include "content/public/browser/browser_thread.h"
+
+namespace extensions {
+
+UpdateClientConfig::UpdateClientConfig() {}
+
+scoped_refptr<base::SequencedTaskRunner>
+UpdateClientConfig::GetSequencedTaskRunner() const {
+  return content::BrowserThread::GetBlockingPool()
+      ->GetSequencedTaskRunnerWithShutdownBehavior(
+          content::BrowserThread::GetBlockingPool()->GetSequenceToken(),
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+}
+
+scoped_refptr<base::SingleThreadTaskRunner>
+UpdateClientConfig::GetSingleThreadTaskRunner() const {
+  return content::BrowserThread::GetMessageLoopProxyForThread(
+      content::BrowserThread::FILE);
+}
+
+UpdateClientConfig::~UpdateClientConfig() {}
+
+}  // namespace extensions
diff --git a/extensions/browser/updater/update_client_config.h b/extensions/browser/updater/update_client_config.h
new file mode 100644
index 0000000..32e7811
--- /dev/null
+++ b/extensions/browser/updater/update_client_config.h
@@ -0,0 +1,40 @@
+// 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 EXTENSIONS_BROWSER_UPDATER_UPDATE_CLIENT_CONFIG_H_
+#define EXTENSIONS_BROWSER_UPDATER_UPDATE_CLIENT_CONFIG_H_
+
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "components/update_client/configurator.h"
+
+namespace base {
+class SequencedTaskRunner;
+class SingleThreadTaskRunner;
+}
+
+namespace extensions {
+
+// Used to provide configuration settings to the UpdateClient.
+class UpdateClientConfig : public update_client::Configurator {
+ public:
+  UpdateClientConfig();
+
+  scoped_refptr<base::SequencedTaskRunner> GetSequencedTaskRunner()
+      const override;
+  scoped_refptr<base::SingleThreadTaskRunner> GetSingleThreadTaskRunner()
+      const override;
+
+ protected:
+  friend class base::RefCountedThreadSafe<UpdateClientConfig>;
+  ~UpdateClientConfig() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(UpdateClientConfig);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_UPDATE_CLIENT_CONFIG_H_
diff --git a/extensions/browser/updater/update_data_provider.cc b/extensions/browser/updater/update_data_provider.cc
new file mode 100644
index 0000000..e0ad403
--- /dev/null
+++ b/extensions/browser/updater/update_data_provider.cc
@@ -0,0 +1,72 @@
+// 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 "extensions/browser/updater/update_data_provider.h"
+
+#include "base/base64.h"
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/stl_util.h"
+#include "base/strings/string_util.h"
+#include "components/update_client/update_client.h"
+#include "content/public/browser/browser_thread.h"
+#include "crypto/sha2.h"
+#include "extensions/browser/content_verifier.h"
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/extension_system.h"
+#include "extensions/browser/updater/update_install_shim.h"
+#include "extensions/common/extension.h"
+
+namespace extensions {
+
+UpdateDataProvider::UpdateDataProvider(content::BrowserContext* context,
+                                       const InstallCallback& callback)
+    : context_(context), callback_(callback) {}
+
+UpdateDataProvider::~UpdateDataProvider() {}
+
+void UpdateDataProvider::Shutdown() {
+  context_ = nullptr;
+}
+
+void UpdateDataProvider::GetData(
+    const std::vector<std::string>& ids,
+    std::vector<update_client::CrxComponent>* data) {
+  if (!context_)
+    return;
+  const ExtensionRegistry* registry = ExtensionRegistry::Get(context_);
+  for (const auto& id : ids) {
+    const Extension* extension = registry->GetInstalledExtension(id);
+    if (!extension)
+      continue;
+    data->push_back(update_client::CrxComponent());
+    update_client::CrxComponent* info = &data->back();
+    std::string pubkey_bytes;
+    base::Base64Decode(extension->public_key(), &pubkey_bytes);
+    info->pk_hash.resize(crypto::kSHA256Length, 0);
+    crypto::SHA256HashString(pubkey_bytes, vector_as_array(&info->pk_hash),
+                             info->pk_hash.size());
+    info->version = *extension->version();
+    info->allow_background_download = false;
+
+    info->installer = new UpdateInstallShim(
+        id, extension->path(),
+        base::Bind(&UpdateDataProvider::RunInstallCallback, this));
+  }
+}
+
+void UpdateDataProvider::RunInstallCallback(const std::string& extension_id,
+                                            const base::FilePath& temp_dir) {
+  if (!context_) {
+    content::BrowserThread::PostBlockingPoolTask(
+        FROM_HERE,
+        base::Bind(base::IgnoreResult(&base::DeleteFile), temp_dir, false));
+    return;
+  } else {
+    callback_.Run(context_, extension_id, temp_dir);
+  }
+}
+
+}  // namespace extensions
diff --git a/extensions/browser/updater/update_data_provider.h b/extensions/browser/updater/update_data_provider.h
new file mode 100644
index 0000000..95cea59
--- /dev/null
+++ b/extensions/browser/updater/update_data_provider.h
@@ -0,0 +1,69 @@
+// 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 EXTENSIONS_BROWSER_UPDATER_UPDATE_DATA_PROVIDER_H_
+#define EXTENSIONS_BROWSER_UPDATER_UPDATE_DATA_PROVIDER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+namespace update_client {
+struct CrxComponent;
+}
+
+namespace extensions {
+
+// This class exists to let an UpdateClient retrieve information about a set of
+// extensions it is doing an update check for.
+class UpdateDataProvider : public base::RefCounted<UpdateDataProvider> {
+ public:
+  typedef base::Callback<void(content::BrowserContext* context,
+                              const std::string& /* extension_id */,
+                              const base::FilePath& /* temp_dir */)>
+      InstallCallback;
+
+  // We need a browser context to use when retrieving data for a set of
+  // extension ids, as well as a callback for proceeding with installation
+  // steps once the UpdateClient has downloaded and unpacked an update for an
+  // extension.
+  UpdateDataProvider(content::BrowserContext* context,
+                     const InstallCallback& callback);
+
+  // Notify this object that the associated browser context is being shut down
+  // the pointer to the context should be dropped and no more work should be
+  // done.
+  void Shutdown();
+
+  // Matches update_client::UpdateClient::CrxDataCallback
+  void GetData(const std::vector<std::string>& ids,
+               std::vector<update_client::CrxComponent>* data);
+
+ private:
+  friend class base::RefCounted<UpdateDataProvider>;
+  ~UpdateDataProvider();
+
+  void RunInstallCallback(const std::string& extension_id,
+                          const base::FilePath& temp_dir);
+
+  content::BrowserContext* context_;
+  InstallCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(UpdateDataProvider);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_UPDATE_DATA_PROVIDER_H_
diff --git a/extensions/browser/updater/update_install_shim.cc b/extensions/browser/updater/update_install_shim.cc
new file mode 100644
index 0000000..4b6f582
--- /dev/null
+++ b/extensions/browser/updater/update_install_shim.cc
@@ -0,0 +1,83 @@
+// 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 "extensions/browser/updater/update_install_shim.h"
+
+#include "base/files/file_enumerator.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/values.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace extensions {
+
+UpdateInstallShim::UpdateInstallShim(std::string extension_id,
+                                     const base::FilePath& extension_root,
+                                     const UpdateInstallShimCallback& callback)
+    : extension_id_(extension_id),
+      extension_root_(extension_root),
+      callback_(callback) {}
+
+void UpdateInstallShim::OnUpdateError(int error) {
+  VLOG(1) << "OnUpdateError (" << extension_id_ << ") " << error;
+}
+
+bool UpdateInstallShim::Install(const base::DictionaryValue& manifest,
+                                const base::FilePath& unpack_path) {
+  base::ScopedTempDir temp_dir;
+  if (!temp_dir.CreateUniqueTempDir())
+    return false;
+
+  // The UpdateClient code will delete unpack_path if it still exists after
+  // this method is done, so we rename it on top of our temp dir.
+  if (!base::DeleteFile(temp_dir.path(), true) ||
+      !base::Move(unpack_path, temp_dir.path())) {
+    LOG(ERROR) << "Trying to install update for " << extension_id_
+               << "and failed to move " << unpack_path.value() << " to  "
+               << temp_dir.path().value();
+    return false;
+  }
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&UpdateInstallShim::RunCallbackOnUIThread, this,
+                 temp_dir.Take()));
+  return true;
+}
+
+bool UpdateInstallShim::GetInstalledFile(const std::string& file,
+                                         base::FilePath* installed_file) {
+  base::FilePath relative_path = base::FilePath::FromUTF8Unsafe(file);
+  if (relative_path.IsAbsolute() || relative_path.ReferencesParent())
+    return false;
+  *installed_file = extension_root_.Append(relative_path);
+  if (!extension_root_.IsParent(*installed_file) ||
+      !base::PathExists(*installed_file)) {
+    VLOG(1) << "GetInstalledFile failed to find " << installed_file->value();
+    installed_file->clear();
+    return false;
+  }
+  return true;
+}
+
+bool UpdateInstallShim::Uninstall() {
+  NOTREACHED();
+  return false;
+}
+
+UpdateInstallShim::~UpdateInstallShim() {}
+
+void UpdateInstallShim::RunCallbackOnUIThread(const base::FilePath& temp_dir) {
+  if (callback_.is_null()) {
+    content::BrowserThread::PostBlockingPoolTask(
+        FROM_HERE, base::Bind(base::IgnoreResult(&base::DeleteFile), temp_dir,
+                              true /*recursive */));
+    return;
+  }
+  callback_.Run(extension_id_, temp_dir);
+}
+
+}  // namespace extensions
diff --git a/extensions/browser/updater/update_install_shim.h b/extensions/browser/updater/update_install_shim.h
new file mode 100644
index 0000000..586e94e
--- /dev/null
+++ b/extensions/browser/updater/update_install_shim.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 EXTENSIONS_BROWSER_UPDATER_UPDATE_INSTALL_SHIM_H_
+#define EXTENSIONS_BROWSER_UPDATER_UPDATE_INSTALL_SHIM_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "components/update_client/update_client.h"
+
+namespace base {
+class DictionaryValue;
+}
+
+namespace extensions {
+
+// A callback to implement the install of a new version of the extension.
+// Takes ownership of the directory at |temp_dir|.
+using UpdateInstallShimCallback =
+    base::Callback<void(const std::string& extension_id,
+                        const base::FilePath& temp_dir)>;
+
+// This class is used as a shim between the components::update_client and
+// extensions code, to help the generic update_client code prepare and then
+// install an updated version of an extension. Because the update_client code
+// doesn't have the notion of extension ids, we use instances of this class to
+// map an install request back to the original update check for a given
+// extension.
+class UpdateInstallShim : public update_client::CrxInstaller {
+ public:
+  // This method takes the id and root directory for an extension we're doing
+  // an update check for, as well as a callback to call if we get a new version
+  // of it to install.
+  UpdateInstallShim(std::string extension_id,
+                    const base::FilePath& extension_root,
+                    const UpdateInstallShimCallback& callback);
+
+  // Called when an update attempt failed.
+  void OnUpdateError(int error) override;
+
+  // This is called when a new version of an extension is unpacked at
+  // |unpack_path| and is ready for install.
+  bool Install(const base::DictionaryValue& manifest,
+               const base::FilePath& unpack_path) override;
+
+  // This is called by the generic differential update code in the
+  // update_client to provide the path to an existing file in the current
+  // version of the extension, so that it can be copied (or serve as the input
+  // to diff-patching) with output going to the directory with the new version
+  // being staged on disk for install.
+  bool GetInstalledFile(const std::string& file,
+                        base::FilePath* installed_file) override;
+
+  // This method is not relevant to extension updating.
+  bool Uninstall() override;
+
+ private:
+  friend class base::RefCountedThreadSafe<UpdateInstallShim>;
+  ~UpdateInstallShim() override;
+
+  // Takes ownership of the directory at path |temp_dir|.
+  void RunCallbackOnUIThread(const base::FilePath& temp_dir);
+
+  std::string extension_id_;
+  base::FilePath extension_root_;
+  UpdateInstallShimCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(UpdateInstallShim);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_UPDATE_INSTALL_SHIM_H_
diff --git a/extensions/browser/updater/update_service.cc b/extensions/browser/updater/update_service.cc
index 0cb055c..ad40abd 100644
--- a/extensions/browser/updater/update_service.cc
+++ b/extensions/browser/updater/update_service.cc
@@ -4,79 +4,61 @@
 
 #include "extensions/browser/updater/update_service.h"
 
-#include <set>
-
-#include "base/message_loop/message_loop.h"
-#include "components/update_client/update_query_params.h"
+#include "base/bind.h"
+#include "base/files/file_util.h"
+#include "components/update_client/update_client.h"
 #include "content/public/browser/browser_context.h"
-#include "extensions/browser/updater/extension_downloader.h"
+#include "extensions/browser/extension_system.h"
+#include "extensions/browser/extensions_browser_client.h"
+#include "extensions/browser/updater/update_data_provider.h"
 #include "extensions/browser/updater/update_service_factory.h"
-#include "extensions/common/extension_urls.h"
 
-using update_client::UpdateQueryParams;
+namespace {
 
-namespace extensions {
+void UpdateCheckCompleteCallback(int error) {}
 
-// static
-UpdateService* UpdateService::Get(content::BrowserContext* context) {
-  return UpdateServiceFactory::GetForBrowserContext(context);
+void InstallUpdateCallback(content::BrowserContext* context,
+                           const std::string& extension_id,
+                           const base::FilePath& temp_dir) {
+  extensions::ExtensionSystem::Get(context)
+      ->InstallUpdate(extension_id, temp_dir);
 }
 
-void UpdateService::DownloadAndInstall(
-    const std::string& id,
-    const base::Callback<void(bool)>& callback) {
-  DCHECK(download_callback_.is_null());
-  download_callback_ = callback;
-  downloader_->AddPendingExtension(id, extension_urls::GetWebstoreUpdateUrl(),
-                                   0);
-  downloader_->StartAllPending(nullptr);
-}
+}  // namespace
 
-UpdateService::UpdateService(content::BrowserContext* context)
-    : browser_context_(context),
-      downloader_(new ExtensionDownloader(this, context->GetRequestContext())) {
-  downloader_->set_manifest_query_params(
-      UpdateQueryParams::Get(UpdateQueryParams::CRX));
-}
+namespace extensions {
 
-UpdateService::~UpdateService() {
+// static
+UpdateService* UpdateService::Get(content::BrowserContext* context) {
+  return UpdateServiceFactory::GetForBrowserContext(context);
 }
 
-void UpdateService::OnExtensionDownloadFailed(
-    const std::string& id,
-    Error error,
-    const PingResult& ping,
-    const std::set<int>& request_ids) {
-  auto callback = download_callback_;
-  download_callback_.Reset();
-  callback.Run(false);
+void UpdateService::Shutdown() {
+  if (update_data_provider_) {
+    update_data_provider_->Shutdown();
+    update_data_provider_ = nullptr;
+  }
+  update_client_ = nullptr;
+  context_ = nullptr;
 }
 
-void UpdateService::OnExtensionDownloadFinished(
-    const CRXFileInfo& file,
-    bool file_ownership_passed,
-    const GURL& download_url,
-    const std::string& version,
-    const PingResult& ping,
-    const std::set<int>& request_id,
-    const InstallCallback& install_callback) {
-  // TODO(rockot): Actually unpack and install the CRX.
-  auto callback = download_callback_;
-  download_callback_.Reset();
-  callback.Run(true);
-  if (!install_callback.is_null())
-    install_callback.Run(true);
+void UpdateService::StartUpdateCheck(std::vector<std::string> extension_ids) {
+  if (!update_client_)
+    return;
+  update_client_->Update(extension_ids, base::Bind(&UpdateDataProvider::GetData,
+                                                   update_data_provider_),
+                         base::Bind(&UpdateCheckCompleteCallback));
 }
 
-bool UpdateService::IsExtensionPending(const std::string& id) {
-  // TODO(rockot): Implement this. For now all IDs are "pending".
-  return true;
+UpdateService::UpdateService(
+    content::BrowserContext* context,
+    scoped_refptr<update_client::UpdateClient> update_client)
+    : context_(context), update_client_(update_client) {
+  CHECK(update_client_);
+  update_data_provider_ =
+      new UpdateDataProvider(context_, base::Bind(&InstallUpdateCallback));
 }
 
-bool UpdateService::GetExtensionExistingVersion(const std::string& id,
-                                                std::string* version) {
-  // TODO(rockot): Implement this.
-  return false;
-}
+UpdateService::~UpdateService() {}
 
 }  // namespace extensions
diff --git a/extensions/browser/updater/update_service.h b/extensions/browser/updater/update_service.h
index 4d19204..0ee321c 100644
--- a/extensions/browser/updater/update_service.h
+++ b/extensions/browser/updater/update_service.h
@@ -6,62 +6,53 @@
 #define EXTENSIONS_BROWSER_UPDATER_UPDATE_SERVICE_H_
 
 #include <string>
+#include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/keyed_service/core/keyed_service.h"
-#include "extensions/browser/updater/extension_downloader_delegate.h"
 
 namespace content {
 class BrowserContext;
 }
 
+namespace update_client {
+class UpdateClient;
+}
+
 namespace extensions {
 
-class ExtensionDownloader;
+class UpdateDataProvider;
+class UpdateService;
 class UpdateServiceFactory;
-class UpdateServiceTest;
 
-// This service manages the download, update, and installation of extensions.
-// It is currently only used by app_shell, but should eventually replace
-// ExtensionUpdater in Chrome.
+// This service manages the autoupdate of extensions.  It should eventually
+// replace ExtensionUpdater in Chrome.
 // TODO(rockot): Replace ExtensionUpdater with this service.
-class UpdateService : public KeyedService, public ExtensionDownloaderDelegate {
+class UpdateService : public KeyedService {
  public:
   static UpdateService* Get(content::BrowserContext* context);
 
-  // TODO(rockot): Remove this. It's a placeholder for a real service interface.
-  // Downloads and (TODO) installs a CRX within the current browser context.
-  void DownloadAndInstall(const std::string& id,
-                          const base::Callback<void(bool)>& callback);
+  void Shutdown() override;
+
+  // Starts an update check for each of |extension_ids|. If there are any
+  // updates available, they will be downloaded, checked for integrity,
+  // unpacked, and then passed off to the ExtensionSystem::InstallUpdate method
+  // for install completion.
+  void StartUpdateCheck(std::vector<std::string> extension_ids);
 
  private:
   friend class UpdateServiceFactory;
-  friend class UpdateServiceTest;
 
-  explicit UpdateService(content::BrowserContext* context);
+  UpdateService(content::BrowserContext* context,
+                scoped_refptr<update_client::UpdateClient> update_client);
   ~UpdateService() override;
 
-  // ExtensionDownloaderDelegate:
-  void OnExtensionDownloadFailed(const std::string& id,
-                                 Error error,
-                                 const PingResult& ping,
-                                 const std::set<int>& request_ids) override;
-  void OnExtensionDownloadFinished(const CRXFileInfo& file,
-                                   bool file_ownership_passed,
-                                   const GURL& download_url,
-                                   const std::string& version,
-                                   const PingResult& ping,
-                                   const std::set<int>& request_id,
-                                   const InstallCallback& callback) override;
-  bool IsExtensionPending(const std::string& id) override;
-  bool GetExtensionExistingVersion(const std::string& id,
-                                   std::string* version) override;
-
-  content::BrowserContext* browser_context_;
-  scoped_ptr<ExtensionDownloader> downloader_;
-  base::Callback<void(bool)> download_callback_;
+  content::BrowserContext* context_;
+
+  scoped_refptr<update_client::UpdateClient> update_client_;
+  scoped_refptr<UpdateDataProvider> update_data_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(UpdateService);
 };
diff --git a/extensions/browser/updater/update_service_browsertest.cc b/extensions/browser/updater/update_service_browsertest.cc
deleted file mode 100644
index 097de35..0000000
--- a/extensions/browser/updater/update_service_browsertest.cc
+++ /dev/null
@@ -1,218 +0,0 @@
-// Copyright 2014 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 <map>
-#include <string>
-#include <utility>
-
-#include "base/bind.h"
-#include "base/files/scoped_temp_dir.h"
-#include "base/run_loop.h"
-#include "base/strings/stringprintf.h"
-#include "content/public/test/test_browser_thread_bundle.h"
-#include "content/public/test/test_utils.h"
-#include "extensions/browser/api/extensions_api_client.h"
-#include "extensions/browser/extensions_browser_client.h"
-#include "extensions/browser/updater/update_service.h"
-#include "extensions/common/extension_urls.h"
-#include "extensions/shell/test/shell_test.h"
-#include "net/base/escape.h"
-#include "net/http/http_status_code.h"
-#include "net/url_request/test_url_fetcher_factory.h"
-
-namespace extensions {
-
-namespace {
-
-using FakeResponse = std::pair<std::string, net::HttpStatusCode>;
-
-// TODO(rockot): In general there's enough mock-Omaha-noise that this might be
-// better placed into some test library code in //components/update_client.
-FakeResponse CreateFakeUpdateResponse(const std::string& id,
-                                      size_t crx_length) {
-  std::string response_text = base::StringPrintf(
-      "<gupdate xmlns=\"http://www.google.com/update2/response\" "
-      "    protocol=\"2.0\" server=\"prod\">\n"
-      "  <daystart elapsed_days=\"2860\" elapsed_seconds=\"42042\"/>\n"
-      "  <app appid=\"%s\" status=\"ok\">\n"
-      "    <updatecheck codebase=\"%s\" fp=\"0\" hash=\"\" hash_sha256=\"\" "
-      "        size=\"%d\" status=\"ok\" version=\"1\"/>\n"
-      "  </app>\n"
-      "</gupdate>\n",
-      id.c_str(),
-      base::StringPrintf("https://fake-omaha-hostname/%s.crx",
-                         id.c_str()).c_str(),
-      static_cast<int>(crx_length));
-  return std::make_pair(response_text, net::HTTP_OK);
-}
-
-FakeResponse CreateFakeUpdateNotFoundResponse() {
-  return std::make_pair(
-      std::string(
-          "<gupdate xmlns=\"http://www.google.com/update2/response\" "
-          "         protocol=\"2.0\" server=\"prod\">\n"
-          "  <daystart elapsed_days=\"4242\" elapsed_seconds=\"42042\"/>\n"
-          "  <app appid=\"\" status=\"error-invalidAppId\">\n"
-          "</gupdate>"),
-      net::HTTP_OK);
-}
-
-bool ExtractKeyValueFromComponent(const std::string& component_str,
-                                  const std::string& target_key,
-                                  std::string* extracted_value) {
-  url::Component component(0, static_cast<int>(component_str.length()));
-  url::Component key, value;
-  while (url::ExtractQueryKeyValue(component_str.c_str(), &component, &key,
-                                   &value)) {
-    if (target_key == component_str.substr(key.begin, key.len)) {
-      *extracted_value = component_str.substr(value.begin, value.len);
-      return true;
-    }
-  }
-  return false;
-}
-
-// This extracts an extension ID from an Omaha update query. Queries have the
-// form https://foo/bar/update?x=id%3Dabcdefghijklmnopqrstuvwxyzaaaaaa%26...
-// This function extracts the 'x' query parameter (e.g. "id%3Dabcdef...."),
-// unescapes its value (to become e.g., "id=abcdef...", and then extracts the
-// 'id' value from the result (e.g. "abcdef...").
-bool ExtractIdFromUpdateQuery(const std::string& query_str, std::string* id) {
-  std::string data_string;
-  if (!ExtractKeyValueFromComponent(query_str, "x", &data_string))
-    return false;
-  data_string = net::UnescapeURLComponent(data_string,
-                                          net::UnescapeRule::URL_SPECIAL_CHARS);
-  if (!ExtractKeyValueFromComponent(data_string, "id", id))
-    return false;
-  EXPECT_EQ(32u, id->size());
-  return true;
-}
-
-void ExpectDownloadSuccess(const base::Closure& continuation, bool success) {
-  EXPECT_TRUE(success) << "Download failed.";
-  continuation.Run();
-}
-
-class FakeUpdateURLFetcherFactory : public net::URLFetcherFactory {
- public:
-  FakeUpdateURLFetcherFactory() { EXPECT_TRUE(dir_.CreateUniqueTempDir()); }
-
-  ~FakeUpdateURLFetcherFactory() override {}
-
-  void RegisterFakeExtension(const std::string& id,
-                             const std::string& contents) {
-    CHECK_EQ(32u, id.size());
-    fake_extensions_.insert(std::make_pair(id, contents));
-  }
-
-  // net::URLFetcherFactory:
-  scoped_ptr<net::URLFetcher> CreateURLFetcher(
-      int id,
-      const GURL& url,
-      net::URLFetcher::RequestType request_type,
-      net::URLFetcherDelegate* delegate) override {
-    if (url.spec().find(extension_urls::GetWebstoreUpdateUrl().spec()) == 0) {
-      // Handle fake Omaha requests.
-      return CreateUpdateManifestFetcher(url, delegate);
-    } else if (url.spec().find("https://fake-omaha-hostname") == 0) {
-      // Handle a fake CRX request.
-      return CreateCrxFetcher(url, delegate);
-    }
-    NOTREACHED();
-    return nullptr;
-  }
-
- private:
-  scoped_ptr<net::URLFetcher> CreateUpdateManifestFetcher(
-      const GURL& url,
-      net::URLFetcherDelegate* delegate) {
-    // If we have a fake CRX for the ID, return a fake update blob for it.
-    // Otherwise return an invalid-ID response.
-    FakeResponse response;
-    std::string extension_id;
-    if (!ExtractIdFromUpdateQuery(url.query(), &extension_id)) {
-      response = CreateFakeUpdateNotFoundResponse();
-    } else {
-      const auto& iter = fake_extensions_.find(extension_id);
-      if (iter == fake_extensions_.end())
-        response = CreateFakeUpdateNotFoundResponse();
-      else
-        response = CreateFakeUpdateResponse(extension_id, iter->second.size());
-    }
-    return scoped_ptr<net::URLFetcher>(
-        new net::FakeURLFetcher(url, delegate, response.first, response.second,
-                                net::URLRequestStatus::SUCCESS));
-  }
-
-  scoped_ptr<net::URLFetcher> CreateCrxFetcher(
-      const GURL& url,
-      net::URLFetcherDelegate* delegate) {
-    FakeResponse response;
-    std::string extension_id = url.path().substr(1, 32);
-    const auto& iter = fake_extensions_.find(extension_id);
-    if (iter == fake_extensions_.end())
-      response = std::make_pair(std::string(), net::HTTP_NOT_FOUND);
-    else
-      response = std::make_pair(iter->second, net::HTTP_OK);
-    net::TestURLFetcher* fetcher =
-        new net::FakeURLFetcher(url, delegate, response.first, response.second,
-                                net::URLRequestStatus::SUCCESS);
-    base::FilePath path = dir_.path().Append(
-        base::FilePath::FromUTF8Unsafe(url.path().substr(1)));
-    fetcher->SetResponseFilePath(path);
-    return scoped_ptr<net::URLFetcher>(fetcher);
-  }
-
-  base::ScopedTempDir dir_;
-
-  std::map<std::string, std::string> fake_extensions_;
-
-  DISALLOW_COPY_AND_ASSIGN(FakeUpdateURLFetcherFactory);
-};
-
-}  // namespace
-
-class UpdateServiceTest : public AppShellTest {
- public:
-  UpdateServiceTest() {}
-  ~UpdateServiceTest() override {}
-
-  void SetUpOnMainThread() override {
-    AppShellTest::SetUpOnMainThread();
-
-    update_service_ = UpdateService::Get(browser_context());
-
-    default_url_fetcher_factory_.reset(new FakeUpdateURLFetcherFactory());
-    url_fetcher_factory_.reset(
-        new net::FakeURLFetcherFactory(default_url_fetcher_factory_.get()));
-  }
-
- protected:
-  void RegisterFakeExtension(const std::string& id,
-                             const std::string& crx_contents) {
-    default_url_fetcher_factory_->RegisterFakeExtension(id, crx_contents);
-  }
-
-  UpdateService* update_service() const { return update_service_; }
-
- private:
-  scoped_ptr<FakeUpdateURLFetcherFactory> default_url_fetcher_factory_;
-  scoped_ptr<net::FakeURLFetcherFactory> url_fetcher_factory_;
-
-  UpdateService* update_service_;
-};
-
-IN_PROC_BROWSER_TEST_F(UpdateServiceTest, DownloadAndInstall) {
-  const char kCrxId[] = "abcdefghijklmnopqrstuvwxyzaaaaaa";
-  const char kCrxContents[] = "Hello, world!";
-  RegisterFakeExtension(kCrxId, kCrxContents);
-
-  base::RunLoop run_loop;
-  update_service()->DownloadAndInstall(
-      kCrxId, base::Bind(ExpectDownloadSuccess, run_loop.QuitClosure()));
-  run_loop.Run();
-}
-
-}  // namespace extensions
diff --git a/extensions/browser/updater/update_service_factory.cc b/extensions/browser/updater/update_service_factory.cc
index a87c88b..e441dc3 100644
--- a/extensions/browser/updater/update_service_factory.cc
+++ b/extensions/browser/updater/update_service_factory.cc
@@ -5,7 +5,9 @@
 #include "extensions/browser/updater/update_service_factory.h"
 
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "components/update_client/update_client.h"
 #include "extensions/browser/extension_registry_factory.h"
+#include "extensions/browser/extensions_browser_client.h"
 #include "extensions/browser/process_manager_factory.h"
 #include "extensions/browser/updater/update_service.h"
 
@@ -27,8 +29,6 @@ UpdateServiceFactory::UpdateServiceFactory()
     : BrowserContextKeyedServiceFactory(
           "UpdateService",
           BrowserContextDependencyManager::GetInstance()) {
-  DependsOn(extensions::ExtensionRegistryFactory::GetInstance());
-  DependsOn(extensions::ProcessManagerFactory::GetInstance());
 }
 
 UpdateServiceFactory::~UpdateServiceFactory() {
@@ -36,7 +36,8 @@ UpdateServiceFactory::~UpdateServiceFactory() {
 
 KeyedService* UpdateServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
-  return new UpdateService(context);
+  return new UpdateService(
+      context, ExtensionsBrowserClient::Get()->CreateUpdateClient(context));
 }
 
 }  // namespace extensions
diff --git a/extensions/browser/updater/update_service_unittest.cc b/extensions/browser/updater/update_service_unittest.cc
new file mode 100644
index 0000000..f570303
--- /dev/null
+++ b/extensions/browser/updater/update_service_unittest.cc
@@ -0,0 +1,248 @@
+// Copyright 2014 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 <vector>
+
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/run_loop.h"
+#include "base/values.h"
+#include "components/crx_file/id_util.h"
+#include "components/update_client/update_client.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "content/public/test/test_utils.h"
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/extensions_test.h"
+#include "extensions/browser/mock_extension_system.h"
+#include "extensions/browser/test_extensions_browser_client.h"
+#include "extensions/browser/updater/update_service.h"
+#include "extensions/common/extension_builder.h"
+#include "extensions/common/value_builder.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+class FakeUpdateClient : public update_client::UpdateClient {
+ public:
+  FakeUpdateClient();
+
+  // Returns the data we've gotten from the CrxDataCallback for ids passed to
+  // the Update function.
+  std::vector<update_client::CrxComponent>* data() { return &data_; }
+
+  // update_client::UpdateClient
+  void AddObserver(Observer* observer) override {}
+  void RemoveObserver(Observer* observer) override {}
+  void Install(const std::string& id,
+               const CrxDataCallback& crx_data_callback,
+               const CompletionCallback& completion_callback) override {}
+  void Update(const std::vector<std::string>& ids,
+              const CrxDataCallback& crx_data_callback,
+              const CompletionCallback& completion_callback) override;
+  bool GetCrxUpdateState(
+      const std::string& id,
+      update_client::CrxUpdateItem* update_item) const override {
+    return false;
+  }
+  bool IsUpdating(const std::string& id) const override { return false; }
+
+ protected:
+  friend class base::RefCounted<FakeUpdateClient>;
+  ~FakeUpdateClient() override {}
+
+  std::vector<update_client::CrxComponent> data_;
+};
+
+FakeUpdateClient::FakeUpdateClient() {}
+
+void FakeUpdateClient::Update(const std::vector<std::string>& ids,
+                              const CrxDataCallback& crx_data_callback,
+                              const CompletionCallback& completion_callback) {
+  crx_data_callback.Run(ids, &data_);
+}
+
+}  // namespace
+
+namespace extensions {
+
+namespace {
+
+// A fake ExtensionSystem that lets us intercept calls to install new
+// versions of an extension.
+class FakeExtensionSystem : public MockExtensionSystem {
+ public:
+  explicit FakeExtensionSystem(content::BrowserContext* context)
+      : MockExtensionSystem(context) {}
+  ~FakeExtensionSystem() override {}
+
+  struct InstallUpdateRequest {
+    std::string extension_id;
+    base::FilePath temp_dir;
+  };
+
+  std::vector<InstallUpdateRequest>* install_requests() {
+    return &install_requests_;
+  }
+
+  void set_install_callback(const base::Closure& callback) {
+    next_install_callback_ = callback;
+  }
+
+  // ExtensionSystem override
+  void InstallUpdate(const std::string& extension_id,
+                     const base::FilePath& temp_dir) override {
+    base::DeleteFile(temp_dir, true /*recursive*/);
+    InstallUpdateRequest request;
+    request.extension_id = extension_id;
+    request.temp_dir = temp_dir;
+    install_requests_.push_back(request);
+    if (!next_install_callback_.is_null()) {
+      base::Closure tmp = next_install_callback_;
+      next_install_callback_.Reset();
+      tmp.Run();
+    }
+  }
+
+ private:
+  std::vector<InstallUpdateRequest> install_requests_;
+  base::Closure next_install_callback_;
+};
+
+class UpdateServiceTest : public ExtensionsTest {
+ public:
+  UpdateServiceTest() {
+    extensions_browser_client()->set_extension_system_factory(
+        &fake_extension_system_factory_);
+  }
+  ~UpdateServiceTest() override {}
+
+  void SetUp() override {
+    ExtensionsTest::SetUp();
+    browser_threads_.reset(new content::TestBrowserThreadBundle(
+        content::TestBrowserThreadBundle::DEFAULT));
+
+    extensions_browser_client()->SetUpdateClientFactory(base::Bind(
+        &UpdateServiceTest::CreateUpdateClient, base::Unretained(this)));
+
+    update_service_ = UpdateService::Get(browser_context());
+  }
+
+ protected:
+  UpdateService* update_service() const { return update_service_; }
+  FakeUpdateClient* update_client() const { return update_client_.get(); }
+
+  update_client::UpdateClient* CreateUpdateClient() {
+    // We only expect that this will get called once, so consider it an error
+    // if our update_client_ is already non-null.
+    EXPECT_EQ(nullptr, update_client_.get());
+    update_client_ = new FakeUpdateClient();
+    return update_client_.get();
+  }
+
+  // Helper function that creates a file at |relative_path| within |directory|
+  // and fills it with |content|.
+  bool AddFileToDirectory(const base::FilePath& directory,
+                          const base::FilePath& relative_path,
+                          const std::string& content) {
+    base::FilePath full_path = directory.Append(relative_path);
+    if (!CreateDirectory(full_path.DirName()))
+      return false;
+    int result = base::WriteFile(full_path, content.data(), content.size());
+    return (static_cast<size_t>(result) == content.size());
+  }
+
+  FakeExtensionSystem* extension_system() {
+    return static_cast<FakeExtensionSystem*>(
+        fake_extension_system_factory_.GetForBrowserContext(browser_context()));
+  }
+
+ private:
+  UpdateService* update_service_;
+  scoped_refptr<FakeUpdateClient> update_client_;
+  scoped_ptr<content::TestBrowserThreadBundle> browser_threads_;
+  MockExtensionSystemFactory<FakeExtensionSystem>
+      fake_extension_system_factory_;
+};
+
+TEST_F(UpdateServiceTest, BasicUpdateOperations) {
+  // Create a temporary directory that a fake extension will live in and fill
+  // it with some test files.
+  base::ScopedTempDir temp_dir;
+  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
+  base::FilePath foo_js(FILE_PATH_LITERAL("foo.js"));
+  base::FilePath bar_html(FILE_PATH_LITERAL("bar/bar.html"));
+  ASSERT_TRUE(AddFileToDirectory(temp_dir.path(), foo_js, "hello"))
+      << "Failed to write " << temp_dir.path().value() << "/" << foo_js.value();
+  ASSERT_TRUE(AddFileToDirectory(temp_dir.path(), bar_html, "world"));
+
+  ExtensionBuilder builder;
+  builder.SetManifest(DictionaryBuilder()
+                          .Set("name", "Foo")
+                          .Set("version", "1.0")
+                          .Set("manifest_version", 2));
+  builder.SetID(crx_file::id_util::GenerateId("whatever"));
+  builder.SetPath(temp_dir.path());
+
+  scoped_refptr<Extension> extension1(builder.Build());
+
+  ExtensionRegistry::Get(browser_context())->AddEnabled(extension1);
+  std::vector<std::string> ids;
+  ids.push_back(extension1->id());
+
+  // Start an update check and verify that the UpdateClient was sent the right
+  // data.
+  update_service()->StartUpdateCheck(ids);
+  std::vector<update_client::CrxComponent>* data = update_client()->data();
+  ASSERT_NE(nullptr, data);
+  ASSERT_EQ(1u, data->size());
+
+  ASSERT_TRUE(data->at(0).version.Equals(*extension1->version()));
+  update_client::CrxInstaller* installer = data->at(0).installer.get();
+  ASSERT_NE(installer, nullptr);
+
+  // The GetInstalledFile method is used when processing differential updates
+  // to get a path to an existing file in an extension. We want to test a
+  // number of scenarios to be user we handle invalid relative paths, don't
+  // accidentally return paths outside the extension's dir, etc.
+  base::FilePath tmp;
+  EXPECT_TRUE(installer->GetInstalledFile(foo_js.MaybeAsASCII(), &tmp));
+  EXPECT_EQ(temp_dir.path().Append(foo_js), tmp) << tmp.value();
+
+  EXPECT_TRUE(installer->GetInstalledFile(bar_html.MaybeAsASCII(), &tmp));
+  EXPECT_EQ(temp_dir.path().Append(bar_html), tmp) << tmp.value();
+
+  EXPECT_FALSE(installer->GetInstalledFile("does_not_exist", &tmp));
+  EXPECT_FALSE(installer->GetInstalledFile("does/not/exist", &tmp));
+  EXPECT_FALSE(installer->GetInstalledFile("/does/not/exist", &tmp));
+  EXPECT_FALSE(installer->GetInstalledFile("C:\\tmp", &tmp));
+
+  base::FilePath system_temp_dir;
+  ASSERT_TRUE(base::GetTempDir(&system_temp_dir));
+  EXPECT_FALSE(
+      installer->GetInstalledFile(system_temp_dir.MaybeAsASCII(), &tmp));
+
+  // Test the install callback.
+  base::ScopedTempDir new_version_dir;
+  ASSERT_TRUE(new_version_dir.CreateUniqueTempDir());
+  scoped_ptr<base::DictionaryValue> new_manifest(
+      extension1->manifest()->value()->DeepCopy());
+  new_manifest->SetString("version", "2.0");
+
+  installer->Install(*new_manifest, new_version_dir.path());
+
+  scoped_refptr<content::MessageLoopRunner> loop_runner =
+      new content::MessageLoopRunner();
+  extension_system()->set_install_callback(loop_runner->QuitClosure());
+  loop_runner->Run();
+
+  std::vector<FakeExtensionSystem::InstallUpdateRequest>* requests =
+      extension_system()->install_requests();
+  ASSERT_EQ(1u, requests->size());
+  EXPECT_EQ(requests->at(0).extension_id, extension1->id());
+  EXPECT_NE(requests->at(0).temp_dir.value(), new_version_dir.path().value());
+}
+
+}  // namespace
+
+}  // namespace extensions
diff --git a/extensions/extensions.gyp b/extensions/extensions.gyp
index c7976da..3c7657e 100644
--- a/extensions/extensions.gyp
+++ b/extensions/extensions.gyp
@@ -111,7 +111,9 @@
         '../components/components.gyp:sessions_content',
         '../components/components.gyp:storage_monitor',
         '../components/components.gyp:ui_zoom',
+        '../components/components.gyp:update_client',
         '../components/components.gyp:variations',
+        '../components/components.gyp:version_info',
         '../components/components.gyp:web_cache_browser',
         '../components/components.gyp:web_modal',
         '../content/content.gyp:content_browser',
diff --git a/extensions/extensions.gypi b/extensions/extensions.gypi
index 450a943..d730681 100644
--- a/extensions/extensions.gypi
+++ b/extensions/extensions.gypi
@@ -752,6 +752,12 @@
       'browser/updater/request_queue_impl.h',
       'browser/updater/safe_manifest_parser.cc',
       'browser/updater/safe_manifest_parser.h',
+      'browser/updater/update_client_config.cc',
+      'browser/updater/update_client_config.h',
+      'browser/updater/update_data_provider.cc',
+      'browser/updater/update_data_provider.h',
+      'browser/updater/update_install_shim.cc',
+      'browser/updater/update_install_shim.h',
       'browser/updater/update_service.cc',
       'browser/updater/update_service.h',
       'browser/updater/update_service_factory.cc',
diff --git a/extensions/extensions_tests.gypi b/extensions/extensions_tests.gypi
index 2019e37..aab6570 100644
--- a/extensions/extensions_tests.gypi
+++ b/extensions/extensions_tests.gypi
@@ -27,7 +27,6 @@
       'browser/guest_view/web_view/web_view_apitest.cc',
       'browser/guest_view/web_view/web_view_apitest.h',
       'browser/guest_view/web_view/web_view_media_access_apitest.cc',
-      'browser/updater/update_service_browsertest.cc',
       'shell/browser/geolocation/geolocation_apitest.cc',
       'shell/browser/shell_browsertest.cc',
       'shell/test/shell_apitest.cc',
@@ -98,6 +97,7 @@
       'browser/extension_throttle_test_support.cc',
       'browser/extension_throttle_test_support.h',
       'browser/extension_throttle_unittest.cc',
+      'browser/updater/update_service_unittest.cc',
       'browser/value_store/leveldb_value_store_unittest.cc',
       'browser/value_store/testing_value_store_unittest.cc',
       'browser/value_store/value_store_change_unittest.cc',
diff --git a/extensions/shell/browser/shell_browser_main_parts.cc b/extensions/shell/browser/shell_browser_main_parts.cc
index 073dacb..0153679 100644
--- a/extensions/shell/browser/shell_browser_main_parts.cc
+++ b/extensions/shell/browser/shell_browser_main_parts.cc
@@ -73,13 +73,6 @@ using content::BrowserThread;
 
 namespace extensions {
 
-namespace {
-
-void CrxInstallComplete(bool success) {
-  VLOG(1) << "CRX download complete. Success: " << success;
-}
-}
-
 ShellBrowserMainParts::ShellBrowserMainParts(
     const content::MainFunctionParams& parameters,
     ShellBrowserMainDelegate* browser_main_delegate)
@@ -211,17 +204,6 @@ void ShellBrowserMainParts::PreMainMessageLoopRun() {
       base::Bind(nacl::NaClProcessHost::EarlyStartup));
 #endif
 
-  // TODO(rockot): Remove this temporary hack test.
-  std::string install_crx_id =
-      cmd->GetSwitchValueASCII(switches::kAppShellInstallCrx);
-  if (install_crx_id.size() != 0) {
-    CHECK(install_crx_id.size() == 32)
-        << "Extension ID must be exactly 32 characters long.";
-    UpdateService* update_service = UpdateService::Get(browser_context_.get());
-    update_service->DownloadAndInstall(install_crx_id,
-                                       base::Bind(CrxInstallComplete));
-  }
-
   devtools_http_handler_.reset(
       content::ShellDevToolsManagerDelegate::CreateHttpHandler(
           browser_context_.get()));
diff --git a/extensions/shell/browser/shell_extension_system.cc b/extensions/shell/browser/shell_extension_system.cc
index 0457491..b6cff6a 100644
--- a/extensions/shell/browser/shell_extension_system.cc
+++ b/extensions/shell/browser/shell_extension_system.cc
@@ -176,6 +176,12 @@ scoped_ptr<ExtensionSet> ShellExtensionSystem::GetDependentExtensions(
   return make_scoped_ptr(new ExtensionSet());
 }
 
+void ShellExtensionSystem::InstallUpdate(const std::string& extension_id,
+                                         const base::FilePath& temp_dir) {
+  NOTREACHED();
+  base::DeleteFile(temp_dir, true /* recursive */);
+}
+
 void ShellExtensionSystem::OnExtensionRegisteredWithRequestContexts(
     scoped_refptr<Extension> extension) {
   ExtensionRegistry* registry = ExtensionRegistry::Get(browser_context_);
diff --git a/extensions/shell/browser/shell_extension_system.h b/extensions/shell/browser/shell_extension_system.h
index f042f2d..ca2cb5e 100644
--- a/extensions/shell/browser/shell_extension_system.h
+++ b/extensions/shell/browser/shell_extension_system.h
@@ -64,6 +64,8 @@ class ShellExtensionSystem : public ExtensionSystem {
   ContentVerifier* content_verifier() override;
   scoped_ptr<ExtensionSet> GetDependentExtensions(
       const Extension* extension) override;
+  void InstallUpdate(const std::string& extension_id,
+                     const base::FilePath& temp_dir) override;
 
  private:
   void OnExtensionRegisteredWithRequestContexts(
diff --git a/extensions/shell/common/switches.cc b/extensions/shell/common/switches.cc
index fbb5783..66bd7e5 100644
--- a/extensions/shell/common/switches.cc
+++ b/extensions/shell/common/switches.cc
@@ -13,9 +13,6 @@ const char kAppShellAllowRoaming[] = "app-shell-allow-roaming";
 // Size for the host window to create (i.e. "800x600").
 const char kAppShellHostWindowSize[] = "app-shell-host-window-size";
 
-// ID of an extension CRX to be downloaded from the web store.
-const char kAppShellInstallCrx[] = "app-shell-install-crx";
-
 // SSID of the preferred WiFi network.
 const char kAppShellPreferredNetwork[] = "app-shell-preferred-network";
 
diff --git a/extensions/shell/common/switches.h b/extensions/shell/common/switches.h
index b6b3932..7cfe1d6 100644
--- a/extensions/shell/common/switches.h
+++ b/extensions/shell/common/switches.h
@@ -12,7 +12,6 @@ namespace switches {
 // alongside the definition of their values in the .cc file.
 extern const char kAppShellAllowRoaming[];
 extern const char kAppShellHostWindowSize[];
-extern const char kAppShellInstallCrx[];
 extern const char kAppShellPreferredNetwork[];
 extern const char kAppShellRefreshToken[];
 extern const char kAppShellUser[];