Introduce "disable-speech-api" content flag and add it to WebView.

content/child/runtime_features.cc

 // Copyright 2013 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 "content/child/runtime_features.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
@@ skipping 106 matching lines @@
   // WebAudio is enabled by default on ARM and X86, if the MediaCodec
   // API is available.
   WebRuntimeFeatures::enableWebAudio(
       !command_line.HasSwitch(switches::kDisableWebAudio) &&
       media::MediaCodecBridge::IsAvailable());
 #else
   if (command_line.HasSwitch(switches::kDisableWebAudio))
     WebRuntimeFeatures::enableWebAudio(false);
 #endif
 
+  if (command_line.HasSwitch(switches::kDisableSpeechAPI))
+    WebRuntimeFeatures::enableScriptedSpeech(false);
+
   if (command_line.HasSwitch(switches::kDisableEncryptedMedia))
     WebRuntimeFeatures::enableEncryptedMedia(false);
 
   if (command_line.HasSwitch(switches::kDisablePrefixedEncryptedMedia))
     WebRuntimeFeatures::enablePrefixedEncryptedMedia(false);
 
   if (command_line.HasSwitch(switches::kDisableFileSystem))
     WebRuntimeFeatures::enableFileSystem(false);
 
   if (command_line.HasSwitch(switches::kEnableExperimentalCanvasFeatures))
@@ skipping 83 matching lines @@
         command_line.GetSwitchValueASCII(switches::kDisableBlinkFeatures), ',',
         &disabled_features);
     for (const std::string& feature : disabled_features) {
       WebRuntimeFeatures::enableFeatureFromString(
           blink::WebString::fromLatin1(feature), false);
     }
   }
 }
 
 }  // namespace content