WebM support for new multipart VP9 string.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index c1ef49e8052b45758fcd1b30b42590a7c65886cd..7b9801a18dbfadde5bad8f9646fb56e3b5f1b551 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -130,6 +130,7 @@
 #include "ipc/ipc_channel_mojo.h"
 #include "ipc/ipc_platform_file.h"
 #include "media/base/media.h"
+#include "media/base/media_switches.h"
 #include "media/media_features.h"
 #include "media/renderers/gpu_video_accelerator_factories.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
@@ -809,6 +810,13 @@ void RenderThreadImpl::Init(
   }
 #endif
 
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableHDROutput) ||
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableNewVp9CodecString)) {
+    media::EnableNewVp9CodecStringSupport();
+  }
+
   memory_pressure_listener_.reset(new base::MemoryPressureListener(
       base::Bind(&RenderThreadImpl::OnMemoryPressure, base::Unretained(this)),
       base::Bind(&RenderThreadImpl::OnSyncMemoryPressure,