Add wrapper class to media for support of VP9 video, and add a command line flag to enable the supp…

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 9250fe2bb710580c57c3a41c32aecf712345d972..bd05e5bcf54d8ee8b068fe934687d467cb697e86 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -657,6 +657,13 @@ const Experiment kExperiments[] = {
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kEnableOpusPlayback)
   },
+  {
+    "enable-vp9-playback",
+    IDS_FLAGS_ENABLE_VP9_PLAYBACK_NAME,
+    IDS_FLAGS_ENABLE_VP9_PLAYBACK_DESCRIPTION,
+    kOsAll,
+    SINGLE_VALUE_TYPE(switches::kEnableVp9Playback)
+  },
 #if defined(USE_ASH)
   {
     "ash-disable-auto-window-placement",