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

content/browser/gpu/gpu_data_manager_impl_private.cc

 // Copyright (c) 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/browser/gpu/gpu_data_manager_impl_private.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 665 matching lines @@
   DCHECK(command_line);
 
   if (ShouldDisableAcceleratedVideoDecode(command_line))
     command_line->AppendSwitch(switches::kDisableAcceleratedVideoDecode);
 #if defined(ENABLE_WEBRTC)
   if (IsFeatureBlacklisted(gpu::GPU_FEATURE_TYPE_ACCELERATED_VIDEO_ENCODE) &&
       !command_line->HasSwitch(switches::kDisableWebRtcHWEncoding))
     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);
 #endif
 }
 
 void GpuDataManagerImplPrivate::AppendGpuCommandLine(
     base::CommandLine* command_line,
     gpu::GpuPreferences* gpu_preferences) const {
   DCHECK(command_line);
@@ skipping 594 matching lines @@
   gpu_info_.context_info_state = gpu::kCollectInfoFatalFailure;
 #if defined(OS_WIN)
   gpu_info_.dx_diagnostics_info_state = gpu::kCollectInfoFatalFailure;
 #endif
   complete_gpu_info_already_requested_ = true;
   // Some observers might be waiting.
   NotifyGpuInfoUpdate();
 }
 
 }  // namespace content