Revert of Disable speech synthesis API for content/ layer.

android_webview/lib/main/aw_main_delegate.cc

 // Copyright (c) 2012 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 "android_webview/lib/main/aw_main_delegate.h"
 
 #include "android_webview/browser/aw_content_browser_client.h"
 #include "android_webview/browser/browser_view_renderer.h"
 #include "android_webview/browser/gpu_memory_buffer_factory_impl.h"
 #include "android_webview/browser/scoped_allow_wait_for_legacy_web_view_api.h"
@@ skipping 60 matching lines @@
   // Fullscreen video with subtitle is not yet supported.
   cl->AppendSwitch(switches::kDisableOverlayFullscreenVideoSubtitle);
 
 #if defined(VIDEO_HOLE)
   // Support EME/L1 with hole-punching.
   cl->AppendSwitch(switches::kMediaDrmEnableNonCompositing);
 #endif
 
   // WebRTC hardware decoding is not supported, internal bug 15075307
   cl->AppendSwitch(switches::kDisableWebRtcHWDecoding);
-
-  // Speech Synthesis backend resides in the chrome layer, not used by WebView.
-  // http://crbug.com/347045 tracks moving the backend to the content layer.
-  cl->AppendSwitch(switches::kDisableSpeechSynthesis);
   return false;
 }
 
 void AwMainDelegate::PreSandboxStartup() {
   // TODO(torne): When we have a separate renderer process, we need to handle
   // being passed open FDs for the resource paks here.
 #if defined(ARCH_CPU_ARM_FAMILY)
   // Create an instance of the CPU class to parse /proc/cpuinfo and cache
   // cpu_brand info.
   base::CPU cpu_info;
@@ skipping 59 matching lines @@
 
 #if defined(VIDEO_HOLE)
 content::ExternalVideoSurfaceContainer*
 AwMainDelegate::CreateExternalVideoSurfaceContainer(
     content::WebContents* web_contents) {
   return new ExternalVideoSurfaceContainerImpl(web_contents);
 }
 #endif
 
 }  // namespace android_webview