Merge to M44: "Put windows vpx hardware decode behind a flag."

Appears broken for many users, so this is not ready to be on by
default.

BUG=499696
TEST=compile
TBR=ananta,nick

Review URL: https://codereview.chromium.org/1223073003

Cr-Commit-Position: refs/heads/master@{#339180}
(cherry picked from commit 628f0c1e9e7faef3bf3acf573aac5cdc82d87261)

Review URL: https://codereview.chromium.org/1243943002 .

Cr-Commit-Position: refs/branch-heads/2403@{#538}
Cr-Branched-From: f54b8097a9c45ed4ad308133d49f05325d6c5070-refs/heads/master@{#330231}

4 files changed, 13 insertions, 3 deletions

diff --git a/content/browser/gpu/gpu_process_host.cc b/content/browser/gpu/gpu_process_host.cc
index 5ad5340..9c72997 100644
--- a/content/browser/gpu/gpu_process_host.cc
+++ b/content/browser/gpu/gpu_process_host.cc
@@ -87,6 +87,9 @@ static const char* const kSwitchNames[] = {
 #if defined(ENABLE_WEBRTC)
   switches::kDisableWebRtcHWEncoding,
 #endif
+#if defined(OS_WIN)
+  switches::kEnableAcceleratedVpxDecode,
+#endif
   switches::kEnableLogging,
   switches::kEnableShareGroupAsyncTextureUpload,
 #if defined(OS_CHROMEOS)
diff --git a/content/common/gpu/media/dxva_video_decode_accelerator.cc b/content/common/gpu/media/dxva_video_decode_accelerator.cc
index 628bccd0..98947ce 100644
--- a/content/common/gpu/media/dxva_video_decode_accelerator.cc
+++ b/content/common/gpu/media/dxva_video_decode_accelerator.cc
@@ -29,6 +29,7 @@
 #include "base/path_service.h"
 #include "base/trace_event/trace_event.h"
 #include "base/win/windows_version.h"
+#include "content/public/common/content_switches.h"
 #include "media/video/video_decode_accelerator.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
@@ -968,8 +969,10 @@ bool DXVAVideoDecodeAccelerator::InitDecoder(media::VideoCodecProfile profile) {
                       "blacklisted version of msmpeg2vdec.dll 6.7.7140",
                       false);
     codec_ = media::kCodecH264;
-  } else if (profile == media::VP8PROFILE_ANY ||
-             profile == media::VP9PROFILE_ANY) {
+  } else if ((profile == media::VP8PROFILE_ANY ||
+              profile == media::VP9PROFILE_ANY) &&
+             base::CommandLine::ForCurrentProcess()->HasSwitch(
+                 switches::kEnableAcceleratedVpxDecode)) {
     int program_files_key = base::DIR_PROGRAM_FILES;
     if (base::win::OSInfo::GetInstance()->wow64_status() ==
         base::win::OSInfo::WOW64_ENABLED) {
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index bc896da..7036d26 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -994,6 +994,9 @@ const char kDisableLegacyIntermediateWindow[] = "disable-legacy-window";
 const char kDisableWin32kRendererLockDown[] =
     "disable-win32k-renderer-lockdown";
 
+// Enables experimental hardware acceleration for VP8/VP9 video decoding.
+const char kEnableAcceleratedVpxDecode[] = "enable-accelerated-vpx-decode";
+
 // DirectWrite FontCache is shared by browser to renderers using shared memory.
 // This switch allows us to pass the shared memory handle to the renderer.
 const char kFontCacheSharedHandle[] = "font-cache-shared-handle";
diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
index c27bee8..f49c4cc 100644
--- a/content/public/common/content_switches.h
+++ b/content/public/common/content_switches.h
@@ -293,9 +293,10 @@ extern const char kDisableThreadedEventHandlingMac[];
 CONTENT_EXPORT extern const char kDeviceScaleFactor[];
 CONTENT_EXPORT extern const char kDisableLegacyIntermediateWindow[];
 CONTENT_EXPORT extern const char kDisableWin32kRendererLockDown[];
-CONTENT_EXPORT extern const char kMemoryPressureThresholdsMb[];
+CONTENT_EXPORT extern const char kEnableAcceleratedVpxDecode[];
 // Switch to pass the font cache shared memory handle to the renderer.
 CONTENT_EXPORT extern const char kFontCacheSharedHandle[];
+CONTENT_EXPORT extern const char kMemoryPressureThresholdsMb[];
 CONTENT_EXPORT extern const char kTraceExportEventsToETW[];
 #endif