Fix to make 'Enable accessibility features.' option change take effect immediately

Add loading and unloading code to SystemOptionsHandler
Add unregister_component_extension to ExtensionService

BUG=chromium-os:11887
TEST=manually confirmed that enabling/disabling a11y features works immediately

Review URL: http://codereview.chromium.org/7129015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@89302 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 77 insertions, 1 deletions

diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index a835f6a..63fc24b 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -191,6 +191,11 @@ void SimpleExtensionLoadPrompt::InstallUIAbort() {
 
 }  // namespace
 
+bool ExtensionService::ComponentExtensionInfo::Equals(
+    const ComponentExtensionInfo& other) const {
+  return other.manifest == manifest && other.root_directory == root_directory;
+}
+
 ExtensionService::ExtensionRuntimeData::ExtensionRuntimeData()
     : background_page_ready(false),
       being_upgraded(false) {
@@ -575,6 +580,18 @@ PendingExtensionManager* ExtensionService::pending_extension_manager() {
   return &pending_extension_manager_;
 }
 
+void ExtensionService::UnregisterComponentExtension(
+    const ComponentExtensionInfo& info) {
+  RegisteredComponentExtensions new_component_extension_manifests;
+  for (RegisteredComponentExtensions::iterator it =
+           component_extension_manifests_.begin();
+       it != component_extension_manifests_.end(); ++it) {
+    if (!it->Equals(info))
+      new_component_extension_manifests.push_back(*it);
+  }
+  component_extension_manifests_.swap(new_component_extension_manifests);
+}
+
 ExtensionService::~ExtensionService() {
   // No need to unload extensions here because they are profile-scoped, and the
   // profile is in the process of being deleted.
@@ -967,6 +984,27 @@ const Extension* ExtensionService::LoadComponentExtension(
   return extension;
 }
 
+void ExtensionService::UnloadComponentExtension(
+    const ComponentExtensionInfo& info) {
+  JSONStringValueSerializer serializer(info.manifest);
+  scoped_ptr<Value> manifest(serializer.Deserialize(NULL, NULL));
+  if (!manifest.get()) {
+    DLOG(ERROR) << "Failed to parse manifest for extension";
+    return;
+  }
+  std::string public_key;
+  std::string public_key_bytes;
+  std::string id;
+  if (!static_cast<DictionaryValue*>(manifest.get())->
+      GetString(extension_manifest_keys::kPublicKey, &public_key) ||
+      !Extension::ParsePEMKeyBytes(public_key, &public_key_bytes) ||
+      !Extension::GenerateId(public_key_bytes, &id)) {
+    DLOG(ERROR) << "Failed to get extension id";
+    return;
+  }
+  UnloadExtension(id, UnloadedExtensionInfo::DISABLE);
+}
+
 void ExtensionService::LoadAllExtensions() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index 3bed716..7aae4ec 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -134,6 +134,8 @@ class ExtensionService
           root_directory(root_directory) {
     }
 
+    bool Equals(const ComponentExtensionInfo& other) const;
+
     // The extension's manifest. This is required for component extensions so
     // that ExtensionService doesn't need to go to disk to load them.
     std::string manifest;
@@ -204,6 +206,9 @@ class ExtensionService
     component_extension_manifests_.push_back(info);
   }
 
+  // Unregisters a component extension from the list of extensions to be loaded
+  void UnregisterComponentExtension(const ComponentExtensionInfo& info);
+
   const FilePath& install_directory() const { return install_directory_; }
 
   AppsPromo* apps_promo() { return &apps_promo_; }
@@ -317,6 +322,9 @@ class ExtensionService
   // Loads particular component extension.
   const Extension* LoadComponentExtension(const ComponentExtensionInfo& info);
 
+  // Unloads particular component extension.
+  void UnloadComponentExtension(const ComponentExtensionInfo& info);
+
   // Loads all known extensions (used by startup and testing code).
   void LoadAllExtensions();
 
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index a87fec7..bce27ee 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -552,7 +552,7 @@ void ProfileImpl::RegisterComponentExtensions() {
   if (g_browser_process->local_state()->
       GetBoolean(prefs::kAccessibilityEnabled)) {
     FilePath path = FilePath(extension_misc::kAccessExtensionPath)
-        .AppendASCII("access_chromevox");
+        .AppendASCII(extension_misc::kChromeVoxDirectoryName);
     std::string manifest =
         ResourceBundle::GetSharedInstance().GetRawDataResource(
             IDR_CHROMEVOX_MANIFEST).as_string();
diff --git a/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc b/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
index 00d6133..45a2474 100644
--- a/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
+++ b/chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
@@ -11,16 +11,24 @@
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
+#include "content/browser/tab_contents/tab_contents.h"
+#include "content/common/json_value_serializer.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/language_preferences.h"
+#include "chrome/browser/extensions/extension_accessibility_api.h"
+#include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/options/chromeos/system_settings_provider.h"
 #include "chrome/common/pref_names.h"
+#include "chrome/common/extensions/extension.h"
+#include "grit/browser_resources.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "grit/locale_settings.h"
 #include "grit/theme_resources.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
 
 SystemOptionsHandler::SystemOptionsHandler()
     : chromeos::CrosOptionsPageUIHandler(
@@ -96,6 +104,26 @@ void SystemOptionsHandler::AccessibilityChangeCallback(const ListValue* args) {
   std::string checked_str;
   args->GetString(0, &checked_str);
   bool accessibility_enabled = (checked_str == "true");
+
   PrefService* pref_service = g_browser_process->local_state();
   pref_service->SetBoolean(prefs::kAccessibilityEnabled, accessibility_enabled);
+
+  ExtensionAccessibilityEventRouter::GetInstance()->
+      SetAccessibilityEnabled(accessibility_enabled);
+
+  // Load/Unload ChromeVox
+  ExtensionService* extension_service =
+      web_ui_->tab_contents()->profile()->GetExtensionService();
+  std::string manifest = ResourceBundle::GetSharedInstance().
+      GetRawDataResource(IDR_CHROMEVOX_MANIFEST).as_string();
+  FilePath path = FilePath(extension_misc::kAccessExtensionPath)
+      .AppendASCII(extension_misc::kChromeVoxDirectoryName);
+  ExtensionService::ComponentExtensionInfo info(manifest, path);
+  if (accessibility_enabled) { // Load ChromeVox
+    extension_service->register_component_extension(info);
+    extension_service->LoadComponentExtension(info);
+  } else { // Unload ChromeVox
+    extension_service->UnloadComponentExtension(info);
+    extension_service->UnregisterComponentExtension(info);
+  }
 }
diff --git a/chrome/common/extensions/extension_constants.cc b/chrome/common/extensions/extension_constants.cc
index ab59539..4761639 100644
--- a/chrome/common/extensions/extension_constants.cc
+++ b/chrome/common/extensions/extension_constants.cc
@@ -412,5 +412,6 @@ const char* kAppLaunchHistogram = "Extensions.AppLaunch";
 #if defined(OS_CHROMEOS)
 const char* kAccessExtensionPath =
     "/usr/share/chromeos-assets/accessibility/extensions";
+const char* kChromeVoxDirectoryName = "access_chromevox";
 #endif
 }
diff --git a/chrome/common/extensions/extension_constants.h b/chrome/common/extensions/extension_constants.h
index 66e039e..1fdd433 100644
--- a/chrome/common/extensions/extension_constants.h
+++ b/chrome/common/extensions/extension_constants.h
@@ -384,6 +384,7 @@ namespace extension_misc {
   // The directory path on a ChromeOS device where accessibility extensions are
   // stored.
   extern const char* kAccessExtensionPath;
+  extern const char* kChromeVoxDirectoryName;
 #endif
 
   // What causes an extension to be installed? Used in histograms, so don't