Moved extension installation from FILE thread. CrxInstaller and friends are now using their own sequenced task runner instead.

BUG=160183
TEST=SandboxedUnpackerTest.*, ExtensionInstallUIBrowserTest.*

Review URL: https://codereview.chromium.org/11369146

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@167991 0039d316-1c4b-4281-b951-d872f2087c98

21 files changed, 177 insertions, 77 deletions

diff --git a/chrome/browser/chromeos/kiosk_mode/kiosk_mode_screensaver.cc b/chrome/browser/chromeos/kiosk_mode/kiosk_mode_screensaver.cc
index 1e4428d..5edee1a 100644
--- a/chrome/browser/chromeos/kiosk_mode/kiosk_mode_screensaver.cc
+++ b/chrome/browser/chromeos/kiosk_mode/kiosk_mode_screensaver.cc
@@ -188,6 +188,8 @@ void KioskModeScreensaver::ScreensaverPathCallback(
           Extension::COMPONENT,
           Extension::NO_FLAGS,
           extensions_dir,
+          content::BrowserThread::GetMessageLoopProxyForThread(
+              content::BrowserThread::FILE),
           new ScreensaverUnpackerClient(
               screensaver_crx,
               base::Bind(
diff --git a/chrome/browser/component_updater/component_updater_service.cc b/chrome/browser/component_updater/component_updater_service.cc
index b141a42..654b9cb 100644
--- a/chrome/browser/component_updater/component_updater_service.cc
+++ b/chrome/browser/component_updater/component_updater_service.cc
@@ -605,7 +605,8 @@ void CrxUpdateService::ParseManifest(const std::string& xml) {
     }
   } else {
     UtilityProcessHost* host = UtilityProcessHost::Create(
-        new ManifestParserBridge(this), BrowserThread::UI);
+        new ManifestParserBridge(this),
+        base::MessageLoopProxy::current());
     host->EnableZygote();
     host->Send(new ChromeUtilityMsg_ParseUpdateManifest(xml));
   }
diff --git a/chrome/browser/extensions/api/management/management_api.cc b/chrome/browser/extensions/api/management/management_api.cc
index 58ec543..d934b99 100644
--- a/chrome/browser/extensions/api/management/management_api.cc
+++ b/chrome/browser/extensions/api/management/management_api.cc
@@ -290,7 +290,9 @@ class SafeManifestJSONParser : public UtilityProcessHostClient {
   void StartWorkOnIOThread() {
     CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
     UtilityProcessHost* host =
-        UtilityProcessHost::Create(this, BrowserThread::IO);
+        UtilityProcessHost::Create(
+            this,
+            base::MessageLoopProxy::current());
     host->EnableZygote();
     host->Send(new ChromeUtilityMsg_ParseJSON(manifest_));
   }
diff --git a/chrome/browser/extensions/crx_installer.cc b/chrome/browser/extensions/crx_installer.cc
index 0ee089b..3c8354c 100644
--- a/chrome/browser/extensions/crx_installer.cc
+++ b/chrome/browser/extensions/crx_installer.cc
@@ -13,10 +13,12 @@
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
+#include "base/sequenced_task_runner.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/utf_string_conversions.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
@@ -105,6 +107,7 @@ CrxInstaller::CrxInstaller(
       requirements_checker_(new extensions::RequirementsChecker()),
       has_requirement_errors_(false),
       install_wait_for_idle_(true) {
+  installer_task_runner_ = frontend_weak->GetFileTaskRunner();
   if (!approval)
     return;
 
@@ -128,19 +131,6 @@ CrxInstaller::CrxInstaller(
 }
 
 CrxInstaller::~CrxInstaller() {
-  // Delete the temp directory and crx file as necessary. Note that the
-  // destructor might be called on any thread, so we post a task to the file
-  // thread to make sure the delete happens there. This is a best effort
-  // operation since the browser can be shutting down so there might not
-  // be a file thread to post to.
-  if (!temp_dir_.value().empty()) {
-    BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-        base::Bind(&extension_file_util::DeleteFile, temp_dir_, true));
-  }
-  if (delete_source_) {
-    BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-        base::Bind(&extension_file_util::DeleteFile, source_file_, false));
-  }
   // Make sure the UI is deleted on the ui thread.
   if (client_) {
     BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, client_);
@@ -158,10 +148,11 @@ void CrxInstaller::InstallCrx(const FilePath& source_file) {
           install_source_,
           creation_flags_,
           install_directory_,
+          installer_task_runner_,
           this));
 
-  if (!BrowserThread::PostTask(
-          BrowserThread::FILE, FROM_HERE,
+  if (!installer_task_runner_->PostTask(
+          FROM_HERE,
           base::Bind(&SandboxedUnpacker::Start, unpacker.get())))
     NOTREACHED();
 }
@@ -173,8 +164,8 @@ void CrxInstaller::InstallUserScript(const FilePath& source_file,
   source_file_ = source_file;
   download_url_ = download_url;
 
-  if (!BrowserThread::PostTask(
-          BrowserThread::FILE, FROM_HERE,
+  if (!installer_task_runner_->PostTask(
+          FROM_HERE,
           base::Bind(&CrxInstaller::ConvertUserScriptOnFileThread, this)))
     NOTREACHED();
 }
@@ -192,8 +183,8 @@ void CrxInstaller::ConvertUserScriptOnFileThread() {
 }
 
 void CrxInstaller::InstallWebApp(const WebApplicationInfo& web_app) {
-  if (!BrowserThread::PostTask(
-          BrowserThread::FILE, FROM_HERE,
+  if (!installer_task_runner_->PostTask(
+          FROM_HERE,
           base::Bind(&CrxInstaller::ConvertWebAppOnFileThread,
                      this,
                      web_app,
@@ -218,7 +209,7 @@ void CrxInstaller::ConvertWebAppOnFileThread(
 }
 
 CrxInstallerError CrxInstaller::AllowInstall(const Extension* extension) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
 
   // Make sure the expected ID matches if one was supplied or if we want to
   // bypass the prompt.
@@ -347,7 +338,7 @@ CrxInstallerError CrxInstaller::AllowInstall(const Extension* extension) {
 }
 
 void CrxInstaller::OnUnpackFailure(const string16& error_message) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
 
   UMA_HISTOGRAM_ENUMERATION("Extensions.UnpackFailureInstallSource",
                             install_source(), Extension::NUM_LOCATIONS);
@@ -363,7 +354,7 @@ void CrxInstaller::OnUnpackSuccess(const FilePath& temp_dir,
                                    const FilePath& extension_dir,
                                    const DictionaryValue* original_manifest,
                                    const Extension* extension) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
 
   UMA_HISTOGRAM_ENUMERATION("Extensions.UnpackSuccessInstallSource",
                             install_source(), Extension::NUM_LOCATIONS);
@@ -462,8 +453,8 @@ void CrxInstaller::ConfirmInstall() {
     AddRef();  // Balanced in Proceed() and Abort().
     client_->ConfirmInstall(this, extension_.get(), show_dialog_callback_);
   } else {
-    if (!BrowserThread::PostTask(
-            BrowserThread::FILE, FROM_HERE,
+    if (!installer_task_runner_->PostTask(
+            FROM_HERE,
             base::Bind(&CrxInstaller::CompleteInstall, this)))
       NOTREACHED();
   }
@@ -471,8 +462,8 @@ void CrxInstaller::ConfirmInstall() {
 }
 
 void CrxInstaller::InstallUIProceed() {
-  if (!BrowserThread::PostTask(
-          BrowserThread::FILE, FROM_HERE,
+  if (!installer_task_runner_->PostTask(
+          FROM_HERE,
           base::Bind(&CrxInstaller::CompleteInstall, this)))
     NOTREACHED();
 
@@ -502,7 +493,7 @@ void CrxInstaller::InstallUIAbort(bool user_initiated) {
 }
 
 void CrxInstaller::CompleteInstall() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
 
   if (!current_version_.empty()) {
     Version current_version(current_version_);
@@ -561,7 +552,7 @@ void CrxInstaller::CompleteInstall() {
 }
 
 void CrxInstaller::ReportFailureFromFileThread(const CrxInstallerError& error) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
   if (!BrowserThread::PostTask(
           BrowserThread::UI, FROM_HERE,
           base::Bind(&CrxInstaller::ReportFailureFromUIThread, this, error))) {
@@ -590,10 +581,13 @@ void CrxInstaller::ReportFailureFromUIThread(const CrxInstallerError& error) {
     client_->OnInstallFailure(error);
 
   NotifyCrxInstallComplete(NULL);
+
+  // Delete temporary files.
+  CleanupTempFiles();
 }
 
 void CrxInstaller::ReportSuccessFromFileThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
 
   // Tracking number of extensions installed by users
   if (install_cause() == extension_misc::INSTALL_CAUSE_USER_DOWNLOAD)
@@ -603,6 +597,9 @@ void CrxInstaller::ReportSuccessFromFileThread() {
           BrowserThread::UI, FROM_HERE,
           base::Bind(&CrxInstaller::ReportSuccessFromUIThread, this)))
     NOTREACHED();
+
+  // Delete temporary files.
+  CleanupTempFiles();
 }
 
 void CrxInstaller::ReportSuccessFromUIThread() {
@@ -654,4 +651,26 @@ void CrxInstaller::NotifyCrxInstallComplete(const Extension* extension) {
       content::Details<const Extension>(extension));
 }
 
+void CrxInstaller::CleanupTempFiles() {
+  if (!installer_task_runner_->RunsTasksOnCurrentThread()) {
+    if (!installer_task_runner_->PostTask(
+            FROM_HERE,
+            base::Bind(&CrxInstaller::CleanupTempFiles, this))) {
+      NOTREACHED();
+    }
+    return;
+  }
+
+  // Delete the temp directory and crx file as necessary.
+  if (!temp_dir_.value().empty()) {
+    extension_file_util::DeleteFile(temp_dir_, true);
+    temp_dir_ = FilePath();
+  }
+
+  if (delete_source_ && !source_file_.value().empty()) {
+    extension_file_util::DeleteFile(source_file_, false);
+    source_file_ = FilePath();
+  }
+}
+
 }  // namespace extensions
diff --git a/chrome/browser/extensions/crx_installer.h b/chrome/browser/extensions/crx_installer.h
index 5d2d195..0f0019f 100644
--- a/chrome/browser/extensions/crx_installer.h
+++ b/chrome/browser/extensions/crx_installer.h
@@ -21,8 +21,13 @@
 #include "sync/api/string_ordinal.h"
 
 class ExtensionService;
+class ExtensionServiceTest;
 class SkBitmap;
 
+namespace base {
+class SequencedTaskRunner;
+}
+
 namespace extensions {
 class ExtensionUpdaterTest;
 class RequirementsChecker;
@@ -184,6 +189,7 @@ class CrxInstaller
   Profile* profile() { return profile_; }
 
  private:
+  friend class ::ExtensionServiceTest;
   friend class ExtensionUpdaterTest;
   friend class ExtensionCrxInstallerTest;
 
@@ -235,6 +241,12 @@ class CrxInstaller
   void ReportSuccessFromUIThread();
   void NotifyCrxInstallComplete(const Extension* extension);
 
+  // Deletes temporary directory and crx file if needed.
+  void CleanupTempFiles();
+
+  // Creates sequenced task runner for extension install file I/O operations.
+  scoped_refptr<base::SequencedTaskRunner> CreateSequencedTaskRunner();
+
   // The file we're installing.
   FilePath source_file_;
 
@@ -371,6 +383,9 @@ class CrxInstaller
 
   bool install_wait_for_idle_;
 
+  // Sequenced task runner where file I/O operations will be performed.
+  scoped_refptr<base::SequencedTaskRunner> installer_task_runner_;
+
   // Used to show the install dialog.
   ExtensionInstallPrompt::ShowDialogCallback show_dialog_callback_;
 
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 9499f21..4063742 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -19,6 +19,7 @@
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
@@ -243,6 +244,11 @@ void ExtensionService::CheckExternalUninstall(const std::string& id) {
   UninstallExtension(id, true, NULL);
 }
 
+void ExtensionService::SetFileTaskRunnerForTesting(
+    base::SequencedTaskRunner* task_runner) {
+  file_task_runner_ = task_runner;
+}
+
 void ExtensionService::ClearProvidersForTesting() {
   external_extension_providers_.clear();
 }
@@ -634,8 +640,8 @@ bool ExtensionService::UpdateExtension(const std::string& id,
                  << " because it is not installed or pending";
     // Delete extension_path since we're not creating a CrxInstaller
     // that would do it for us.
-    if (!BrowserThread::PostTask(
-            BrowserThread::FILE, FROM_HERE,
+    if (!GetFileTaskRunner()->PostTask(
+            FROM_HERE,
             base::Bind(
                 &extension_file_util::DeleteFile, extension_path, false)))
       NOTREACHED();
@@ -826,8 +832,8 @@ bool ExtensionService::UninstallExtension(
 
   // Tell the backend to start deleting installed extensions on the file thread.
   if (Extension::LOAD != extension->location()) {
-    if (!BrowserThread::PostTask(
-            BrowserThread::FILE, FROM_HERE,
+    if (!GetFileTaskRunner()->PostTask(
+            FROM_HERE,
             base::Bind(
                 &extension_file_util::UninstallExtension,
                 install_directory_,
@@ -1238,6 +1244,22 @@ bool ExtensionService::is_ready() {
   return ready_;
 }
 
+base::SequencedTaskRunner* ExtensionService::GetFileTaskRunner() {
+  if (file_task_runner_)
+    return file_task_runner_;
+
+  // We should be able to interrupt any part of extension install process during
+  // shutdown. SKIP_ON_SHUTDOWN ensures that not started extension install tasks
+  // will be ignored/deleted while we will block on started tasks.
+  std::string token("ext_install-");
+  token.append(profile_->GetPath().AsUTF8Unsafe());
+  file_task_runner_ = BrowserThread::GetBlockingPool()->
+      GetSequencedTaskRunnerWithShutdownBehavior(
+        BrowserThread::GetBlockingPool()->GetNamedSequenceToken(token),
+        base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+  return file_task_runner_;
+}
+
 extensions::ExtensionUpdater* ExtensionService::updater() {
   return updater_.get();
 }
@@ -1982,8 +2004,8 @@ void ExtensionService::GarbageCollectExtensions() {
     extension_paths.insert(std::make_pair(info->at(i)->extension_id,
                                           info->at(i)->extension_path));
 
-  if (!BrowserThread::PostTask(
-          BrowserThread::FILE, FROM_HERE,
+  if (!GetFileTaskRunner()->PostTask(
+          FROM_HERE,
           base::Bind(
               &extension_file_util::GarbageCollectExtensions,
               install_directory_,
@@ -2284,8 +2306,8 @@ void ExtensionService::OnExtensionInstalled(
 
       // Delete the extension directory since we're not going to
       // load it.
-      if (!BrowserThread::PostTask(
-              BrowserThread::FILE, FROM_HERE,
+      if (!GetFileTaskRunner()->PostTask(
+              FROM_HERE,
               base::Bind(&extension_file_util::DeleteFile,
                          extension->path(), true))) {
         NOTREACHED();
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index 23ef9aa..23542e9 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -50,6 +50,10 @@ class GURL;
 class Profile;
 class Version;
 
+namespace base {
+class SequencedTaskRunner;
+}
+
 namespace chromeos {
 class ExtensionInputMethodEventRouter;
 }
@@ -132,6 +136,9 @@ class ExtensionServiceInterface : public syncer::SyncableService {
       const extensions::Extension& extension) = 0;
 
   virtual bool is_ready() = 0;
+
+  // Returns task runner for crx installation file I/O operations.
+  virtual base::SequencedTaskRunner* GetFileTaskRunner() = 0;
 };
 
 // Manages installed and running Chromium extensions.
@@ -509,6 +516,8 @@ class ExtensionService
   // Whether the extension service is ready.
   virtual bool is_ready() OVERRIDE;
 
+  virtual base::SequencedTaskRunner* GetFileTaskRunner() OVERRIDE;
+
   extensions::ComponentLoader* component_loader() {
     return component_loader_.get();
   }
@@ -561,6 +570,9 @@ class ExtensionService
   // externally managed extension.  If so, uninstall it.
   void CheckExternalUninstall(const std::string& id);
 
+  // Changes sequenced task runner for crx installation tasks to |task_runner|.
+  void SetFileTaskRunnerForTesting(base::SequencedTaskRunner* task_runner);
+
   // Clear all ExternalProviders.
   void ClearProvidersForTesting();
 
@@ -955,6 +967,8 @@ class ExtensionService
   extensions::AppShortcutManager app_shortcut_manager_;
 
   scoped_ptr<ExtensionErrorUI> extension_error_ui_;
+  // Sequenced task runner for extension related file operations.
+  scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
 
 #if defined(ENABLE_EXTENSIONS)
   scoped_ptr<extensions::ExtensionActionStorageManager>
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index 007dcd3..0793270 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -436,6 +436,7 @@ void ExtensionServiceTestBase::InitializeExtensionService(
           CommandLine::ForCurrentProcess(),
           extensions_install_dir,
           autoupdate_enabled);
+  service_->SetFileTaskRunnerForTesting(loop_.message_loop_proxy());
   service_->set_extensions_enabled(true);
   service_->set_show_extensions_prompts(false);
   service_->set_install_updates_when_idle_for_test(false);
@@ -679,7 +680,6 @@ class ExtensionServiceTest
         << "Path does not exist: "<< crx_path.value().c_str();
     // no client (silent install)
     scoped_refptr<CrxInstaller> installer(CrxInstaller::Create(service_, NULL));
-
     installer->set_install_source(install_location);
     installer->InstallCrx(crx_path);
 
@@ -5814,7 +5814,7 @@ TEST_F(ExtensionServiceTest, WipeOutExtension) {
       data_dir_.AppendASCII("good.crx"));
 
   service_->CheckForExternalUpdates();
-  loop_.RunAllPending();
+  loop_.RunUntilIdle();
   EXPECT_FALSE(extensions::HasExternalInstallError(service_));
   EXPECT_FALSE(service_->IsExtensionEnabled(good_crx));
   EXPECT_TRUE(service_->IsExtensionEnabled(page_action));
diff --git a/chrome/browser/extensions/sandboxed_unpacker.cc b/chrome/browser/extensions/sandboxed_unpacker.cc
index a9a9179..f1d4c88 100644
--- a/chrome/browser/extensions/sandboxed_unpacker.cc
+++ b/chrome/browser/extensions/sandboxed_unpacker.cc
@@ -16,6 +16,7 @@
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
+#include "base/sequenced_task_runner.h"
 #include "base/utf_string_conversions.h"  // TODO(viettrungluu): delete me.
 #include "chrome/browser/extensions/crx_file.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ -177,19 +178,20 @@ SandboxedUnpacker::SandboxedUnpacker(
     Extension::Location location,
     int creation_flags,
     const FilePath& extensions_dir,
+    base::SequencedTaskRunner* unpacker_io_task_runner,
     SandboxedUnpackerClient* client)
     : crx_path_(crx_path),
-      thread_identifier_(BrowserThread::ID_COUNT),
       run_out_of_process_(run_out_of_process),
       client_(client),
       extensions_dir_(extensions_dir),
       got_response_(false),
       location_(location),
-      creation_flags_(creation_flags) {
+      creation_flags_(creation_flags),
+      unpacker_io_task_runner_(unpacker_io_task_runner) {
 }
 
 bool SandboxedUnpacker::CreateTempDirectory() {
-  CHECK(BrowserThread::GetCurrentThreadIdentifier(&thread_identifier_));
+  CHECK(unpacker_io_task_runner_->RunsTasksOnCurrentThread());
 
   FilePath temp_dir;
   if (!FindWritableTempLocation(extensions_dir_, &temp_dir)) {
@@ -216,7 +218,7 @@ bool SandboxedUnpacker::CreateTempDirectory() {
 void SandboxedUnpacker::Start() {
   // We assume that we are started on the thread that the client wants us to do
   // file IO on.
-  CHECK(BrowserThread::GetCurrentThreadIdentifier(&thread_identifier_));
+  CHECK(unpacker_io_task_runner_->RunsTasksOnCurrentThread());
 
   unpack_start_time_ = base::TimeTicks::Now();
 
@@ -293,9 +295,6 @@ void SandboxedUnpacker::Start() {
 }
 
 SandboxedUnpacker::~SandboxedUnpacker() {
-  base::FileUtilProxy::Delete(
-      BrowserThread::GetMessageLoopProxyForThread(thread_identifier_),
-      temp_dir_.Take(), true, base::FileUtilProxy::StatusCallback());
 }
 
 bool SandboxedUnpacker::OnMessageReceived(const IPC::Message& message) {
@@ -325,7 +324,7 @@ void SandboxedUnpacker::OnProcessCrashed(int exit_code) {
 
 void SandboxedUnpacker::StartProcessOnIOThread(const FilePath& temp_crx_path) {
   UtilityProcessHost* host = UtilityProcessHost::Create(
-      this, thread_identifier_);
+      this, unpacker_io_task_runner_);
   // Grant the subprocess access to the entire subdir the extension file is
   // in, so that it can unpack to that dir.
   host->SetExposedDir(temp_crx_path.DirName());
@@ -336,9 +335,7 @@ void SandboxedUnpacker::StartProcessOnIOThread(const FilePath& temp_crx_path) {
 
 void SandboxedUnpacker::OnUnpackExtensionSucceeded(
     const DictionaryValue& manifest) {
-  // Skip check for unittests.
-  if (thread_identifier_ != BrowserThread::ID_COUNT)
-    CHECK(BrowserThread::CurrentlyOn(thread_identifier_));
+  CHECK(unpacker_io_task_runner_->RunsTasksOnCurrentThread());
   got_response_ = true;
 
   scoped_ptr<DictionaryValue> final_manifest(RewriteManifestFile(manifest));
@@ -391,7 +388,7 @@ void SandboxedUnpacker::OnUnpackExtensionSucceeded(
 }
 
 void SandboxedUnpacker::OnUnpackExtensionFailed(const string16& error) {
-  CHECK(BrowserThread::CurrentlyOn(thread_identifier_));
+  CHECK(unpacker_io_task_runner_->RunsTasksOnCurrentThread());
   got_response_ = true;
   ReportFailure(
       UNPACKER_CLIENT_FAILED,
@@ -569,7 +566,7 @@ void SandboxedUnpacker::ReportFailure(FailureReason reason,
                             reason, NUM_FAILURE_REASONS);
   UMA_HISTOGRAM_TIMES("Extensions.SandboxUnpackFailureTime",
                       base::TimeTicks::Now() - unpack_start_time_);
-
+  Cleanup();
   client_->OnUnpackFailure(error);
 }
 
@@ -792,4 +789,12 @@ bool SandboxedUnpacker::RewriteCatalogFiles() {
   return true;
 }
 
+void SandboxedUnpacker::Cleanup() {
+  DCHECK(unpacker_io_task_runner_->RunsTasksOnCurrentThread());
+  if (!temp_dir_.Delete()) {
+    LOG(WARNING) << "Can not delete temp directory at "
+                 << temp_dir_.path().value();
+  }
+}
+
 }  // namespace extensions
diff --git a/chrome/browser/extensions/sandboxed_unpacker.h b/chrome/browser/extensions/sandboxed_unpacker.h
index 22abb5f..67af256 100644
--- a/chrome/browser/extensions/sandboxed_unpacker.h
+++ b/chrome/browser/extensions/sandboxed_unpacker.h
@@ -16,6 +16,7 @@
 
 namespace base {
 class DictionaryValue;
+class SequencedTaskRunner;
 }
 
 namespace extensions {
@@ -77,6 +78,7 @@ class SandboxedUnpacker : public content::UtilityProcessHostClient {
                     Extension::Location location,
                     int creation_flags,
                     const FilePath& extensions_dir,
+                    base::SequencedTaskRunner* unpacker_io_task_runner,
                     SandboxedUnpackerClient* client);
 
   // Start unpacking the extension. The client is called with the results.
@@ -187,12 +189,12 @@ class SandboxedUnpacker : public content::UtilityProcessHostClient {
   bool RewriteImageFiles();
   bool RewriteCatalogFiles();
 
+  // Cleans up temp directory artifacts.
+  void Cleanup();
+
   // The path to the CRX to unpack.
   FilePath crx_path_;
 
-  // Our client's thread. This is the thread we respond on.
-  content::BrowserThread::ID thread_identifier_;
-
   // True if unpacking should be done by the utility process.
   bool run_out_of_process_;
 
@@ -230,6 +232,9 @@ class SandboxedUnpacker : public content::UtilityProcessHostClient {
   // Creation flags to use for the extension.  These flags will be used
   // when calling Extenion::Create() by the crx installer.
   int creation_flags_;
+
+  // Sequenced task runner where file I/O operations will be performed at.
+  scoped_refptr<base::SequencedTaskRunner> unpacker_io_task_runner_;
 };
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/sandboxed_unpacker_unittest.cc b/chrome/browser/extensions/sandboxed_unpacker_unittest.cc
index c16f325..11c4dd1 100644
--- a/chrome/browser/extensions/sandboxed_unpacker_unittest.cc
+++ b/chrome/browser/extensions/sandboxed_unpacker_unittest.cc
@@ -104,13 +104,12 @@ class SandboxedUnpackerTest : public testing::Test {
     ASSERT_TRUE(file_util::CreateDirectory(temp_path_));
 
     sandboxed_unpacker_ =
-        new SandboxedUnpacker(crx_path, false, Extension::INTERNAL,
-                              Extension::NO_FLAGS, extensions_dir_.path(),
-                              client_);
+        new SandboxedUnpacker(
+            crx_path, false, Extension::INTERNAL, Extension::NO_FLAGS,
+            extensions_dir_.path(),
+            BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
+            client_);
 
-    // Hack since SandboxedUnpacker gets its background thread id from
-    // the Start call, but we don't call it here.
-    sandboxed_unpacker_->thread_identifier_ = BrowserThread::FILE;
     EXPECT_TRUE(PrepareUnpackerEnv());
   }
 
diff --git a/chrome/browser/extensions/test_extension_service.cc b/chrome/browser/extensions/test_extension_service.cc
index 16d5bc2..46871cd 100644
--- a/chrome/browser/extensions/test_extension_service.cc
+++ b/chrome/browser/extensions/test_extension_service.cc
@@ -105,6 +105,11 @@ bool TestExtensionService::is_ready() {
   return false;
 }
 
+base::SequencedTaskRunner* TestExtensionService::GetFileTaskRunner() {
+  ADD_FAILURE();
+  return NULL;
+}
+
 void TestExtensionService::AddExtension(const Extension* extension) {
   ADD_FAILURE();
 }
diff --git a/chrome/browser/extensions/test_extension_service.h b/chrome/browser/extensions/test_extension_service.h
index 0c0b27f..11b95e2 100644
--- a/chrome/browser/extensions/test_extension_service.h
+++ b/chrome/browser/extensions/test_extension_service.h
@@ -65,6 +65,8 @@ class TestExtensionService : public ExtensionServiceInterface {
 
   virtual bool is_ready() OVERRIDE;
 
+  virtual base::SequencedTaskRunner* GetFileTaskRunner() OVERRIDE;
+
   virtual void AddExtension(const extensions::Extension* extension) OVERRIDE;
 
   virtual void UnloadExtension(
diff --git a/chrome/browser/extensions/updater/safe_manifest_parser.cc b/chrome/browser/extensions/updater/safe_manifest_parser.cc
index 7287122..920a2ff 100644
--- a/chrome/browser/extensions/updater/safe_manifest_parser.cc
+++ b/chrome/browser/extensions/updater/safe_manifest_parser.cc
@@ -51,7 +51,7 @@ void SafeManifestParser::ParseInSandbox() {
       !CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess);
   if (use_utility_process) {
     content::UtilityProcessHost* host = content::UtilityProcessHost::Create(
-        this, BrowserThread::UI);
+        this, BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI));
     host->EnableZygote();
     host->Send(new ChromeUtilityMsg_ParseUpdateManifest(xml_));
   } else {
diff --git a/chrome/browser/extensions/webstore_install_helper.cc b/chrome/browser/extensions/webstore_install_helper.cc
index 950fbb6..2b27dd5 100644
--- a/chrome/browser/extensions/webstore_install_helper.cc
+++ b/chrome/browser/extensions/webstore_install_helper.cc
@@ -74,7 +74,8 @@ void WebstoreInstallHelper::Start() {
 void WebstoreInstallHelper::StartWorkOnIOThread() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   utility_host_ =
-      UtilityProcessHost::Create(this, BrowserThread::IO)->AsWeakPtr();
+      UtilityProcessHost::Create(
+          this, base::MessageLoopProxy::current())->AsWeakPtr();
   utility_host_->EnableZygote();
   utility_host_->StartBatchMode();
 
diff --git a/chrome/browser/extensions/webstore_standalone_installer.cc b/chrome/browser/extensions/webstore_standalone_installer.cc
index bb3e38b..7686908 100644
--- a/chrome/browser/extensions/webstore_standalone_installer.cc
+++ b/chrome/browser/extensions/webstore_standalone_installer.cc
@@ -81,7 +81,8 @@ class SafeWebstoreResponseParser : public UtilityProcessHostClient {
   void StartWorkOnIOThread() {
     CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
     UtilityProcessHost* host =
-        UtilityProcessHost::Create(this, BrowserThread::IO);
+        UtilityProcessHost::Create(
+            this, base::MessageLoopProxy::current());
     host->EnableZygote();
     host->Send(new ChromeUtilityMsg_ParseJSON(webstore_data_));
   }
diff --git a/chrome/browser/image_decoder.cc b/chrome/browser/image_decoder.cc
index 1f456ee..6d7b948 100644
--- a/chrome/browser/image_decoder.cc
+++ b/chrome/browser/image_decoder.cc
@@ -62,7 +62,7 @@ void ImageDecoder::DecodeImageInSandbox(
     const std::vector<unsigned char>& image_data) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   UtilityProcessHost* utility_process_host = UtilityProcessHost::Create(
-      this, target_thread_id_);
+      this, BrowserThread::GetMessageLoopProxyForThread(target_thread_id_));
   utility_process_host->EnableZygote();
   if (image_codec_ == ROBUST_JPEG_CODEC) {
     utility_process_host->Send(
diff --git a/chrome/browser/importer/external_process_importer_client.cc b/chrome/browser/importer/external_process_importer_client.cc
index 36dc21d..bcec842 100644
--- a/chrome/browser/importer/external_process_importer_client.cc
+++ b/chrome/browser/importer/external_process_importer_client.cc
@@ -261,7 +261,9 @@ void ExternalProcessImporterClient::NotifyItemFinishedOnIOThread(
 void ExternalProcessImporterClient::StartProcessOnIOThread(
     BrowserThread::ID thread_id) {
   utility_process_host_ =
-      UtilityProcessHost::Create(this, thread_id)->AsWeakPtr();
+      UtilityProcessHost::Create(
+          this,
+          BrowserThread::GetMessageLoopProxyForThread(thread_id))->AsWeakPtr();
   utility_process_host_->DisableSandbox();
 
 #if defined(OS_MACOSX)
diff --git a/chrome/browser/themes/browser_theme_pack.cc b/chrome/browser/themes/browser_theme_pack.cc
index c6dd5ad..3a47e65 100644
--- a/chrome/browser/themes/browser_theme_pack.cc
+++ b/chrome/browser/themes/browser_theme_pack.cc
@@ -10,6 +10,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
@@ -516,7 +517,6 @@ scoped_refptr<BrowserThemePack> BrowserThemePack::BuildFromDataPack(
 }
 
 bool BrowserThemePack::WriteToDisk(const FilePath& path) const {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   // Add resources for each of the property arrays.
   RawDataForWriting resources;
   resources[kHeaderID] = base::StringPiece(
@@ -1100,9 +1100,6 @@ void BrowserThemePack::CreateTabBackgroundImages(ImageCache* images) const {
 
 void BrowserThemePack::RepackImages(const ImageCache& images,
                                     RawImages* reencoded_images) const {
-
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-
   typedef std::vector<ui::ScaleFactor> ScaleFactors;
   for (ImageCache::const_iterator it = images.begin();
        it != images.end(); ++it) {
@@ -1150,7 +1147,6 @@ void BrowserThemePack::CopyImagesTo(const ImageCache& source,
 
 void BrowserThemePack::AddRawImagesTo(const RawImages& images,
                                       RawDataForWriting* out) const {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   for (RawImages::const_iterator it = images.begin(); it != images.end();
        ++it) {
     (*out)[it->first] = base::StringPiece(
diff --git a/chrome/browser/themes/theme_service.cc b/chrome/browser/themes/theme_service.cc
index e1f660d..027315d 100644
--- a/chrome/browser/themes/theme_service.cc
+++ b/chrome/browser/themes/theme_service.cc
@@ -6,10 +6,12 @@
 
 #include "base/bind.h"
 #include "base/memory/ref_counted_memory.h"
+#include "base/sequenced_task_runner.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/themes/browser_theme_pack.h"
@@ -194,7 +196,8 @@ const int kToolbarButtonIDs[] = {
 };
 
 // Writes the theme pack to disk on a separate thread.
-void WritePackToDiskCallback(BrowserThemePack* pack, const FilePath& path) {
+void WritePackToDiskCallback(BrowserThemePack* pack,
+                             const FilePath& path) {
   if (!pack->WriteToDisk(path))
     NOTREACHED() << "Could not write theme pack to disk";
 }
@@ -682,10 +685,15 @@ void ThemeService::BuildFromExtension(const Extension* extension) {
     return;
   }
 
+  ExtensionService* service =
+      extensions::ExtensionSystem::Get(profile_)->extension_service();
+  if (!service)
+    return;
+
   // Write the packed file to disk.
   FilePath pack_path = extension->path().Append(chrome::kThemePackFilename);
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
+  service->GetFileTaskRunner()->PostTask(
+      FROM_HERE,
       base::Bind(&WritePackToDiskCallback, pack, pack_path));
 
   SavePackName(pack_path);
diff --git a/chrome/browser/web_resource/json_asynchronous_unpacker.cc b/chrome/browser/web_resource/json_asynchronous_unpacker.cc
index f797a2f..44dcbbc 100644
--- a/chrome/browser/web_resource/json_asynchronous_unpacker.cc
+++ b/chrome/browser/web_resource/json_asynchronous_unpacker.cc
@@ -105,7 +105,8 @@ class JSONAsynchronousUnpackerImpl
 
   void StartProcessOnIOThread(BrowserThread::ID thread_id,
                               const std::string& json_data) {
-    UtilityProcessHost* host = UtilityProcessHost::Create(this, thread_id);
+    UtilityProcessHost* host = UtilityProcessHost::Create(
+        this, BrowserThread::GetMessageLoopProxyForThread(thread_id));
     host->EnableZygote();
     // TODO(mrc): get proper file path when we start using web resources
     // that need to be unpacked.