Android: enable/disable WebRTC HW H264 with a flag.

content/browser/gpu/gpu_data_manager_impl_private.cc

Index: content/browser/gpu/gpu_data_manager_impl_private.cc
diff --git a/content/browser/gpu/gpu_data_manager_impl_private.cc b/content/browser/gpu/gpu_data_manager_impl_private.cc
index 96beb775df9b3160d7e407bce87e51bc90d2cc36..4cb3a471021c8a78a2bf8e9253cf82fa9950894e 100644
--- a/content/browser/gpu/gpu_data_manager_impl_private.cc
+++ b/content/browser/gpu/gpu_data_manager_impl_private.cc
@@ -683,6 +683,13 @@ void GpuDataManagerImplPrivate::AppendRendererCommandLine(
     command_line->AppendSwitch(switches::kDisableWebRtcHWEncoding);
 #endif
 
+// Disable HW encoding by default on Android.
+#if defined(ENABLE_WEBRTC) && defined(OS_ANDROID)
+  if (!command_line->HasSwitch(switches::kDisableWebRtcHWEncoding)) {
+    command_line->AppendSwitch(switches::kDisableWebRtcHWEncoding);
+  }

[Ken Russell (switch to Gerrit), 2016/10/06 23:23:09]

Is there a reason to not just handle this with a new entry in
src/gpu/config/software_rendering_list_json.cc ? If not, please add a new entry
there with a description and link to the bug ID, and don't forget to increment
the version number at the top of the file. Thanks.

[braveyao, 2016/10/06 23:31:05]

There was one in software_rendering_list_json.cc which was recently removed in
cl https://codereview.chromium.org/2288103003. 
When I firstly started this cl, it took me a while to find out the entry in the
software_rendering_list_json.cc. So this time I added it here.
Do you think it's better to add it back to the software_rendering_list_json.cc
in this cl?

[Ken Russell (switch to Gerrit), 2016/10/07 00:46:51]

Yes, please just add the entry back in software_rendering_list_json.cc. There's
already a way to do this so it's best not to add another way. Also, by putting
it in software_rendering_list_json.cc there's a way to optionally enable it,
where doing it this way that would require a recompile.

[braveyao, 2016/10/07 00:59:23]

Done.

+#endif
+
 #if defined(USE_AURA)
   if (!CanUseGpuBrowserCompositor())
     command_line->AppendSwitch(switches::kDisableGpuCompositing);