disable web audio by default on android and add switches to enable it

content/browser/renderer_host/render_process_host_impl.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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #if defined(OS_WIN)
@@ skipping 729 matching lines @@
     switches::kDisableLocalStorage,
     switches::kDisableLogging,
     switches::kDisablePointerLock,
     switches::kDisableSeccompFilterSandbox,
     switches::kDisableSeccompSandbox,
     switches::kDisableSessionStorage,
     switches::kDisableSharedWorkers,
     switches::kDisableSpeechInput,
     switches::kEnableScriptedSpeech,
     switches::kDisableThreadedAnimation,
+#if defined(OS_ANDROID)
+    switches::kEnableWebAudio,
+#else
     switches::kDisableWebAudio,
+#endif
     switches::kDisableWebSockets,
     switches::kDomAutomationController,
     switches::kEnableAcceleratedVideoDecode,
     switches::kEnableAccessibilityLogging,
     switches::kEnableDCHECK,
     switches::kEnableEncryptedMedia,
     switches::kEnableFixedLayout,
     switches::kEnableGPUServiceLogging,
     switches::kEnableGPUClientLogging,
     switches::kEnableGpuBenchmarking,
@@ skipping 741 matching lines @@
       int32 route_id,
       int32 gpu_process_host_id) {
   TRACE_EVENT0("renderer_host",
                "RenderWidgetHostImpl::OnCompositorSurfaceBuffersSwappedNoHost");
   RenderWidgetHostImpl::AcknowledgeBufferPresent(route_id,
                                                  gpu_process_host_id,
                                                  0);
 }
 
 }  // namespace content