Remove ChromeVox manifest file read from UI thread.

Fixes a DCHECK by making ChromeVox extension load asynchronous.

This was broken in r272781 (https://codereview.chromium.org/295123002) when
the manifest was moved from the .pak file to its own file on disk.

BUG=

Review URL: https://codereview.chromium.org/323623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276277 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 159 insertions, 76 deletions

diff --git a/chrome/browser/chromeos/accessibility/accessibility_manager.cc b/chrome/browser/chromeos/accessibility/accessibility_manager.cc
index 91a66ae..66bfb63 100644
--- a/chrome/browser/chromeos/accessibility/accessibility_manager.cc
+++ b/chrome/browser/chromeos/accessibility/accessibility_manager.cc
@@ -12,6 +12,8 @@
 #include "ash/shell.h"
 #include "ash/sticky_keys/sticky_keys_controller.h"
 #include "ash/system/tray/system_tray_notifier.h"
+#include "base/callback.h"
+#include "base/callback_helpers.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/metrics/histogram.h"
@@ -157,50 +159,77 @@ class ContentScriptLoader {
   std::queue<extensions::ExtensionResource> resources_;
 };
 
-void LoadChromeVoxExtension(Profile* profile,
-                            RenderViewHost* render_view_host) {
+void InjectChromeVoxContentScript(
+    ExtensionService* extension_service,
+    int render_process_id,
+    int render_view_id,
+    const base::Closure& done_cb);
+
+void LoadChromeVoxExtension(
+    Profile* profile,
+    RenderViewHost* render_view_host,
+    base::Closure done_cb) {
   ExtensionService* extension_service =
       extensions::ExtensionSystem::Get(profile)->extension_service();
-  std::string extension_id =
-      extension_service->component_loader()->AddChromeVoxExtension();
   if (render_view_host) {
-    ExtensionService* extension_service =
-        extensions::ExtensionSystem::Get(profile)->extension_service();
-    const extensions::Extension* extension =
-        extension_service->extensions()->GetByID(extension_id);
-
-    // Set a flag to tell ChromeVox that it's just been enabled,
-    // so that it won't interrupt our speech feedback enabled message.
-    ExtensionMsg_ExecuteCode_Params params;
-    params.request_id = 0;
-    params.extension_id = extension->id();
-    params.is_javascript = true;
-    params.code = "window.INJECTED_AFTER_LOAD = true;";
-    params.run_at = extensions::UserScript::DOCUMENT_IDLE;
-    params.all_frames = true;
-    params.match_about_blank = false;
-    params.in_main_world = false;
-    render_view_host->Send(new ExtensionMsg_ExecuteCode(
-        render_view_host->GetRoutingID(), params));
-
-    // Inject ChromeVox' content scripts.
-    ContentScriptLoader* loader = new ContentScriptLoader(
-        extension->id(), render_view_host->GetProcess()->GetID(),
-        render_view_host->GetRoutingID());
-
-    const extensions::UserScriptList& content_scripts =
-        extensions::ContentScriptsInfo::GetContentScripts(extension);
-    for (size_t i = 0; i < content_scripts.size(); i++) {
-      const extensions::UserScript& script = content_scripts[i];
-      for (size_t j = 0; j < script.js_scripts().size(); ++j) {
-        const extensions::UserScript::File &file = script.js_scripts()[j];
-        extensions::ExtensionResource resource = extension->GetResource(
-            file.relative_path());
-        loader->AppendScript(resource);
-      }
+    // Wrap the passed in callback to inject the content script.
+    done_cb = base::Bind(
+        &InjectChromeVoxContentScript,
+        extension_service,
+        render_view_host->GetProcess()->GetID(),
+        render_view_host->GetRoutingID(),
+        done_cb);
+  }
+  extension_service->component_loader()->AddChromeVoxExtension(done_cb);
+}
+
+void InjectChromeVoxContentScript(
+    ExtensionService* extension_service,
+    int render_process_id,
+    int render_view_id,
+    const base::Closure& done_cb) {
+  // Make sure to always run |done_cb|.  ChromeVox was loaded even if we end up
+  // not injecting into this particular render view.
+  base::ScopedClosureRunner done_runner(done_cb);
+  RenderViewHost* render_view_host =
+      RenderViewHost::FromID(render_process_id, render_view_id);
+  if (!render_view_host)
+    return;
+  const extensions::Extension* extension =
+      extension_service->extensions()->GetByID(
+          extension_misc::kChromeVoxExtensionId);
+
+  // Set a flag to tell ChromeVox that it's just been enabled,
+  // so that it won't interrupt our speech feedback enabled message.
+  ExtensionMsg_ExecuteCode_Params params;
+  params.request_id = 0;
+  params.extension_id = extension->id();
+  params.is_javascript = true;
+  params.code = "window.INJECTED_AFTER_LOAD = true;";
+  params.run_at = extensions::UserScript::DOCUMENT_IDLE;
+  params.all_frames = true;
+  params.match_about_blank = false;
+  params.in_main_world = false;
+  render_view_host->Send(new ExtensionMsg_ExecuteCode(
+      render_view_host->GetRoutingID(), params));
+
+  // Inject ChromeVox' content scripts.
+  ContentScriptLoader* loader = new ContentScriptLoader(
+      extension->id(), render_view_host->GetProcess()->GetID(),
+      render_view_host->GetRoutingID());
+
+  const extensions::UserScriptList& content_scripts =
+      extensions::ContentScriptsInfo::GetContentScripts(extension);
+  for (size_t i = 0; i < content_scripts.size(); i++) {
+    const extensions::UserScript& script = content_scripts[i];
+    for (size_t j = 0; j < script.js_scripts().size(); ++j) {
+      const extensions::UserScript::File &file = script.js_scripts()[j];
+      extensions::ExtensionResource resource = extension->GetResource(
+          file.relative_path());
+      loader->AppendScript(resource);
     }
-    loader->Run();  // It cleans itself up when done.
   }
+  loader->Run();  // It cleans itself up when done.
 }
 
 void UnloadChromeVoxExtension(Profile* profile) {
@@ -523,19 +552,22 @@ void AccessibilityManager::UpdateSpokenFeedbackFromPref() {
 }
 
 void AccessibilityManager::LoadChromeVox() {
+  base::Closure done_cb = base::Bind(&AccessibilityManager::PostLoadChromeVox,
+                                     weak_ptr_factory_.GetWeakPtr(),
+                                     profile_);
   ScreenLocker* screen_locker = ScreenLocker::default_screen_locker();
   if (screen_locker && screen_locker->locked()) {
     // If on the lock screen, loads ChromeVox only to the lock screen as for
     // now. On unlock, it will be loaded to the user screen.
     // (see. AccessibilityManager::Observe())
-    LoadChromeVoxToLockScreen();
+    LoadChromeVoxToLockScreen(done_cb);
   } else {
-    LoadChromeVoxToUserScreen();
+    LoadChromeVoxToUserScreen(done_cb);
   }
-  PostLoadChromeVox(profile_);
 }
 
-void AccessibilityManager::LoadChromeVoxToUserScreen() {
+void AccessibilityManager::LoadChromeVoxToUserScreen(
+    const base::Closure& done_cb) {
   if (chrome_vox_loaded_on_user_screen_)
     return;
 
@@ -556,12 +588,15 @@ void AccessibilityManager::LoadChromeVoxToUserScreen() {
     chrome_vox_loaded_on_lock_screen_ = true;
   }
 
-  LoadChromeVoxExtension(profile_, login_web_ui ?
-      login_web_ui->GetWebContents()->GetRenderViewHost() : NULL);
   chrome_vox_loaded_on_user_screen_ = true;
+  LoadChromeVoxExtension(
+      profile_, login_web_ui ?
+      login_web_ui->GetWebContents()->GetRenderViewHost() : NULL,
+      done_cb);
 }
 
-void AccessibilityManager::LoadChromeVoxToLockScreen() {
+void AccessibilityManager::LoadChromeVoxToLockScreen(
+    const base::Closure& done_cb) {
   if (chrome_vox_loaded_on_lock_screen_)
     return;
 
@@ -570,9 +605,11 @@ void AccessibilityManager::LoadChromeVoxToLockScreen() {
     content::WebUI* lock_web_ui = screen_locker->GetAssociatedWebUI();
     if (lock_web_ui) {
       Profile* profile = Profile::FromWebUI(lock_web_ui);
-      LoadChromeVoxExtension(profile,
-          lock_web_ui->GetWebContents()->GetRenderViewHost());
       chrome_vox_loaded_on_lock_screen_ = true;
+      LoadChromeVoxExtension(
+          profile,
+          lock_web_ui->GetWebContents()->GetRenderViewHost(),
+          done_cb);
     }
   }
 }
@@ -925,7 +962,7 @@ base::TimeDelta AccessibilityManager::PlayShutdownSound() {
 }
 
 void AccessibilityManager::InjectChromeVox(RenderViewHost* render_view_host) {
-  LoadChromeVoxExtension(profile_, render_view_host);
+  LoadChromeVoxExtension(profile_, render_view_host, base::Closure());
 }
 
 scoped_ptr<AccessibilityStatusSubscription>
@@ -1013,16 +1050,13 @@ void AccessibilityManager::Observe(
     case chrome::NOTIFICATION_SCREEN_LOCK_STATE_CHANGED: {
       bool is_screen_locked = *content::Details<bool>(details).ptr();
       if (spoken_feedback_enabled_) {
-        if (is_screen_locked) {
-          LoadChromeVoxToLockScreen();
-
-          // Status tray gets verbalized by user screen ChromeVox, so we need
-          // this as well.
-          LoadChromeVoxToUserScreen();
-        } else {
-          // If spoken feedback was enabled, also enable it on the user screen.
-          LoadChromeVoxToUserScreen();
-        }
+        if (is_screen_locked)
+          LoadChromeVoxToLockScreen(base::Closure());
+        // If spoken feedback was enabled, make sure it is also enabled on
+        // the user screen.
+        // The status tray gets verbalized by user screen ChromeVox, so we need
+        // to load it on the user screen even if the screen is locked.
+        LoadChromeVoxToUserScreen(base::Closure());
       }
       break;
     }
diff --git a/chrome/browser/chromeos/accessibility/accessibility_manager.h b/chrome/browser/chromeos/accessibility/accessibility_manager.h
index 91a4f4c..fa3f336 100644
--- a/chrome/browser/chromeos/accessibility/accessibility_manager.h
+++ b/chrome/browser/chromeos/accessibility/accessibility_manager.h
@@ -9,6 +9,7 @@
 
 #include "ash/accessibility_delegate.h"
 #include "ash/session/session_state_observer.h"
+#include "base/callback_forward.h"
 #include "base/callback_list.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
@@ -195,8 +196,8 @@ class AccessibilityManager
 
  private:
   void LoadChromeVox();
-  void LoadChromeVoxToUserScreen();
-  void LoadChromeVoxToLockScreen();
+  void LoadChromeVoxToUserScreen(const base::Closure& done_cb);
+  void LoadChromeVoxToLockScreen(const base::Closure& done_cb);
   void UnloadChromeVox();
   void UnloadChromeVoxFromLockScreen();
   void PostLoadChromeVox(Profile* profile);
diff --git a/chrome/browser/extensions/component_loader.cc b/chrome/browser/extensions/component_loader.cc
index cca90da..debe6cf 100644
--- a/chrome/browser/extensions/component_loader.cc
+++ b/chrome/browser/extensions/component_loader.cc
@@ -21,6 +21,7 @@
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/pref_names.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/plugin_service.h"
@@ -57,6 +58,8 @@
 #include "grit/chromium_strings.h"
 #endif
 
+using content::BrowserThread;
+
 namespace extensions {
 
 namespace {
@@ -97,6 +100,19 @@ std::string GenerateId(const base::DictionaryValue* manifest,
   return id;
 }
 
+#if defined(OS_CHROMEOS)
+scoped_ptr<base::DictionaryValue>
+LoadManifestOnFileThread(
+    const base::FilePath& chromevox_path, const char* manifest_filename) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
+  std::string error;
+  scoped_ptr<base::DictionaryValue> manifest(
+      file_util::LoadManifest(chromevox_path, manifest_filename, &error));
+  CHECK(manifest) << error;
+  return manifest.Pass();
+}
+#endif  // defined(OS_CHROMEOS)
+
 }  // namespace
 
 ComponentLoader::ComponentExtensionInfo::ComponentExtensionInfo(
@@ -117,7 +133,8 @@ ComponentLoader::ComponentLoader(ExtensionServiceInterface* extension_service,
     : profile_prefs_(profile_prefs),
       local_state_(local_state),
       browser_context_(browser_context),
-      extension_service_(extension_service) {}
+      extension_service_(extension_service),
+      weak_factory_(this) {}
 
 ComponentLoader::~ComponentLoader() {
   ClearAllRegistered();
@@ -329,24 +346,38 @@ void ComponentLoader::AddNetworkSpeechSynthesisExtension() {
 }
 
 #if defined(OS_CHROMEOS)
-std::string ComponentLoader::AddChromeVoxExtension() {
-  base::FilePath chromevox_path;
-  PathService::Get(chrome::DIR_RESOURCES, &chromevox_path);
-  chromevox_path =
-      chromevox_path.Append(extension_misc::kChromeVoxExtensionPath);
+void ComponentLoader::AddChromeVoxExtension(
+    const base::Closure& done_cb) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  base::FilePath resources_path;
+  PathService::Get(chrome::DIR_RESOURCES, &resources_path);
+  base::FilePath chromevox_path =
+      resources_path.Append(extension_misc::kChromeVoxExtensionPath);
 
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   const char* manifest_filename =
       command_line->HasSwitch(chromeos::switches::kGuestSession) ?
       extension_misc::kChromeVoxGuestManifestFilename :
           extension_misc::kChromeVoxManifestFilename;
-
-  std::string error;
-  scoped_ptr<base::DictionaryValue> manifest(
-      file_util::LoadManifest(chromevox_path, manifest_filename, &error));
-  CHECK(manifest) << error;
-
-  return Add(manifest.release(), chromevox_path);
+  BrowserThread::PostTaskAndReplyWithResult(
+      BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&LoadManifestOnFileThread, chromevox_path, manifest_filename),
+      base::Bind(&ComponentLoader::AddChromeVoxExtensionWithManifest,
+                 weak_factory_.GetWeakPtr(),
+                 chromevox_path,
+                 done_cb));
+}
+
+void ComponentLoader::AddChromeVoxExtensionWithManifest(
+    const base::FilePath& chromevox_path,
+    const base::Closure& done_cb,
+    scoped_ptr<base::DictionaryValue> manifest) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  std::string extension_id = Add(manifest.release(), chromevox_path);
+  CHECK_EQ(extension_misc::kChromeVoxExtensionId, extension_id);
+  if (!done_cb.is_null())
+    done_cb.Run();
 }
 
 std::string ComponentLoader::AddChromeOsSpeechSynthesisExtension() {
@@ -543,7 +574,7 @@ void ComponentLoader::AddDefaultComponentExtensionsWithBackgroundPages(
   // Load ChromeVox extension now if spoken feedback is enabled.
   if (chromeos::AccessibilityManager::Get() &&
       chromeos::AccessibilityManager::Get()->IsSpokenFeedbackEnabled()) {
-    AddChromeVoxExtension();
+    AddChromeVoxExtension(base::Closure());
   }
 #endif  // defined(OS_CHROMEOS)
 
diff --git a/chrome/browser/extensions/component_loader.h b/chrome/browser/extensions/component_loader.h
index 735184f..8e09727 100644
--- a/chrome/browser/extensions/component_loader.h
+++ b/chrome/browser/extensions/component_loader.h
@@ -8,8 +8,10 @@
 #include <string>
 #include <vector>
 
+#include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
+#include "base/memory/weak_ptr.h"
 #include "base/values.h"
 
 class ExtensionServiceInterface;
@@ -97,7 +99,10 @@ class ComponentLoader {
   void Reload(const std::string& extension_id);
 
 #if defined(OS_CHROMEOS)
-  std::string AddChromeVoxExtension();
+  // Calls |done_cb|, if not a null callback, on success.
+  // NOTE: |done_cb| is not called if the component loader is shut down
+  // during loading.
+  void AddChromeVoxExtension(const base::Closure& done_cb);
   std::string AddChromeOsSpeechSynthesisExtension();
 #endif
 
@@ -146,6 +151,16 @@ class ComponentLoader {
   // Enable HTML5 FileSystem for given component extension in Guest mode.
   void EnableFileSystemInGuestMode(const std::string& id);
 
+#if defined(OS_CHROMEOS)
+  // Used as a reply callback when loading the ChromeVox extension.
+  // Called with a |chromevox_path| and parsed |manifest| and invokes
+  // |done_cb| after adding the extension.
+  void AddChromeVoxExtensionWithManifest(
+      const base::FilePath& chromevox_path,
+      const base::Closure& done_cb,
+      scoped_ptr<base::DictionaryValue> manifest);
+#endif
+
   PrefService* profile_prefs_;
   PrefService* local_state_;
   content::BrowserContext* browser_context_;
@@ -156,6 +171,8 @@ class ComponentLoader {
   typedef std::vector<ComponentExtensionInfo> RegisteredComponentExtensions;
   RegisteredComponentExtensions component_extensions_;
 
+  base::WeakPtrFactory<ComponentLoader> weak_factory_;
+
   FRIEND_TEST_ALL_PREFIXES(TtsApiTest, NetworkSpeechEngine);
   FRIEND_TEST_ALL_PREFIXES(TtsApiTest, NoNetworkSpeechEngineWhenOffline);