Add Espeak component extension support behind a flag

See bug for more context; the Espeak extension provides
a lower-quality speech engine that supports many more
languages, enabling us to support virtually all world
languages out-of-the-box on Chrome OS without requiring
a separate download.

This new engine must be in a separate component
extension due to having a different license.

This patch puts the extension load behind a flag,
--enable-experimental-accessibility-features, because
it needs some more polish before we launch it to
all users.

Bug: 862710
TBR=michaelpg@chromium.org

Change-Id: Ia4d010fa5ff217928a3a66d17543bd4990d24c10
Reviewed-on: https://chromium-review.googlesource.com/c/1247038
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601852}

chrome/browser/extensions/component_extensions_whitelist/whitelist.cc

@@ -31,8 +31,9 @@ bool IsComponentExtensionWhitelisted(const std::string& extension_id) {
 #if defined(OS_CHROMEOS)
     extension_misc::kAssessmentAssistantExtensionId,
     extension_misc::kChromeVoxExtensionId,
+    extension_misc::kEspeakSpeechSynthesisExtensionId,
+    extension_misc::kGoogleSpeechSynthesisExtensionId,
     extension_misc::kSelectToSpeakExtensionId,
-    extension_misc::kSpeechSynthesisExtensionId,
     extension_misc::kSwitchAccessExtensionId,
     extension_misc::kZipArchiverExtensionId,
 #endif

chrome/browser/extensions/component_loader.cc

@@ -351,13 +351,20 @@ void ComponentLoader::AddNetworkSpeechSynthesisExtension() {
 }
 
 #if defined(OS_CHROMEOS)
-void ComponentLoader::AddChromeOsSpeechSynthesisExtension() {
+void ComponentLoader::AddChromeOsSpeechSynthesisExtensions() {
   AddComponentFromDir(
-      base::FilePath(extension_misc::kSpeechSynthesisExtensionPath),
-      extension_misc::kSpeechSynthesisExtensionId,
-      base::Bind(&ComponentLoader::EnableFileSystemInGuestMode,
-                 weak_factory_.GetWeakPtr(),
-                 extension_misc::kSpeechSynthesisExtensionId));
+      base::FilePath(extension_misc::kGoogleSpeechSynthesisExtensionPath),
+      extension_misc::kGoogleSpeechSynthesisExtensionId,
+      base::BindRepeating(&ComponentLoader::EnableFileSystemInGuestMode,
+                          weak_factory_.GetWeakPtr(),
+                          extension_misc::kGoogleSpeechSynthesisExtensionId));
+
+  if (chromeos::switches::AreExperimentalAccessibilityFeaturesEnabled()) {
+    AddComponentFromDir(
+        base::FilePath(extension_misc::kEspeakSpeechSynthesisExtensionPath),
+        extension_misc::kEspeakSpeechSynthesisExtensionId,
+        base::RepeatingClosure());
+  }
 }
 #endif
 

chrome/browser/extensions/component_loader.h

@@ -110,7 +110,7 @@ class ComponentLoader {
                                         const std::string& name_string,
                                         const std::string& description_string);
 
-  void AddChromeOsSpeechSynthesisExtension();
+  void AddChromeOsSpeechSynthesisExtensions();
 #endif
 
   void set_ignore_whitelist_for_testing(bool value) {

chrome/browser/speech/extension_api/tts_engine_extension_api.cc

@@ -321,17 +321,17 @@ bool TtsExtensionEngine::LoadBuiltInTtsExtension(
     content::BrowserContext* browser_context) {
 #if defined(OS_CHROMEOS)
   Profile* profile = Profile::FromBrowserContext(browser_context);
-  // Check to see if the engine was previously loaded.
+  // Check to see if one of the engines was previously loaded.
   if (TtsEngineExtensionObserver::GetInstance(profile)->SawExtensionLoad(
-          extension_misc::kSpeechSynthesisExtensionId, true)) {
+          extension_misc::kGoogleSpeechSynthesisExtensionId, true)) {
     return false;
   }
 
-  // Load the component extension into this profile.
+  // Load the component extensions into this profile.
   extensions::ExtensionService* extension_service =
       extensions::ExtensionSystem::Get(profile)->extension_service();
   DCHECK(extension_service);
-  extension_service->component_loader()->AddChromeOsSpeechSynthesisExtension();
+  extension_service->component_loader()->AddChromeOsSpeechSynthesisExtensions();
   return true;
 #else
   return false;

chrome/browser/ui/webui/settings/tts_handler.cc

@@ -176,7 +176,7 @@ void TtsHandler::WakeTtsEngine(const base::ListValue* args) {
   Profile* profile = Profile::FromWebUI(web_ui());
   TtsExtensionEngine::GetInstance()->LoadBuiltInTtsExtension(profile);
   extensions::ProcessManager::Get(profile)->WakeEventPage(
-      extension_misc::kSpeechSynthesisExtensionId,
+      extension_misc::kGoogleSpeechSynthesisExtensionId,
       base::BindOnce(&TtsHandler::OnTtsEngineAwake,
                      weak_factory_.GetWeakPtr()));
 }

chrome/common/extensions/extension_constants.cc

@@ -59,9 +59,13 @@ const char kConnectivityDiagnosticsPath[] =
 const char kConnectivityDiagnosticsLauncherPath[] =
     "/usr/share/chromeos-assets/connectivity_diagnostics_launcher";
 const char kFirstRunDialogId[] = "jdgcneonijmofocbhmijhacgchbihela";
-const char kSpeechSynthesisExtensionPath[] =
+const char kEspeakSpeechSynthesisExtensionPath[] =
+    "/usr/share/chromeos-assets/speech_synthesis/espeak-ng";
+const char kEspeakSpeechSynthesisExtensionId[] =
+    "dakbfdmgjiabojdgbiljlhgjbokobjpg";
+const char kGoogleSpeechSynthesisExtensionPath[] =
     "/usr/share/chromeos-assets/speech_synthesis/patts";
-const char kSpeechSynthesisExtensionId[] =
+const char kGoogleSpeechSynthesisExtensionId[] =
     "gjjabgpgjpampikjhjpfhneeoapjbjaf";
 const char kWallpaperManagerId[] = "obklkkbkpaoaejdabbfldmcfplpdgolj";
 const char kZipArchiverExtensionId[] = "dmboannefpncccogfdikhmhpmdnddgoe";

chrome/common/extensions/extension_constants.h

@@ -215,10 +215,14 @@ extern const char kConnectivityDiagnosticsPath[];
 extern const char kConnectivityDiagnosticsLauncherPath[];
 // The extension id of the first run dialog application.
 extern const char kFirstRunDialogId[];
-// Path to preinstalled speech synthesis extension.
-extern const char kSpeechSynthesisExtensionPath[];
-// The extension id of the speech synthesis extension.
-extern const char kSpeechSynthesisExtensionId[];
+// Path to preinstalled Google speech synthesis extension.
+extern const char kGoogleSpeechSynthesisExtensionPath[];
+// The extension id of the Google speech synthesis extension.
+extern const char kGoogleSpeechSynthesisExtensionId[];
+// Path to preinstalled eSpeak-NG speech synthesis extension.
+extern const char kEspeakSpeechSynthesisExtensionPath[];
+// The extension id of the eSpeak-NG speech synthesis extension.
+extern const char kEspeakSpeechSynthesisExtensionId[];
 // The extension id of the wallpaper manager application.
 extern const char kWallpaperManagerId[];
 // The extension id of the zip archiver extension.