media: Remove VP9 flag, and enable VP9 support by default.

media/base/media_switches.h

 // 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.
 
 // Defines all the "media" command-line switches.
 
 #ifndef MEDIA_BASE_MEDIA_SWITCHES_H_
 #define MEDIA_BASE_MEDIA_SWITCHES_H_
 
 #include "build/build_config.h"
 #include "media/base/media_export.h"
 
 namespace switches {
 
 MEDIA_EXPORT extern const char kAudioBufferSize[];
 
 MEDIA_EXPORT extern const char kEnableEac3Playback[];
 
 MEDIA_EXPORT extern const char kEnableOpusPlayback[];
 
 MEDIA_EXPORT extern const char kEnableVp8AlphaPlayback[];
 
-MEDIA_EXPORT extern const char kEnableVp9Playback[];
-
 MEDIA_EXPORT extern const char kVideoThreads[];
 
 #if defined(GOOGLE_TV)
 MEDIA_EXPORT extern const char kUseExternalVideoSurfaceThresholdInPixels[];
 #endif
 
 #if defined(OS_LINUX) || defined(OS_FREEBSD) || defined(OS_SOLARIS)
 MEDIA_EXPORT extern const char kAlsaInputDevice[];
 MEDIA_EXPORT extern const char kAlsaOutputDevice[];
 #endif
 
 #if defined(OS_MACOSX)
 MEDIA_EXPORT extern const char kDisableMainThreadAudio[];
 #endif
 
 #if defined(OS_WIN)
 MEDIA_EXPORT extern const char kEnableExclusiveAudio[];
 MEDIA_EXPORT extern const char kForceWaveAudio[];
 MEDIA_EXPORT extern const char kWaveOutBuffers[];
 #endif
 
 #if defined(USE_CRAS)
 MEDIA_EXPORT extern const char kUseCras[];
 #endif
 
 }  // namespace switches
 
 #endif  // MEDIA_BASE_MEDIA_SWITCHES_H_