Add flag to enable MJPEG acceleration for video capture

content/browser/renderer_host/gpu_jpeg_decoder.cc

Index: content/browser/renderer_host/gpu_jpeg_decoder.cc
diff --git a/content/browser/renderer_host/gpu_jpeg_decoder.cc b/content/browser/renderer_host/gpu_jpeg_decoder.cc
index 362dbfda525f2fe8d61f777a62690df189ed609f..ba44386e75a3898b19d86b087eb1ffc015109599 100644
--- a/content/browser/renderer_host/gpu_jpeg_decoder.cc
+++ b/content/browser/renderer_host/gpu_jpeg_decoder.cc
@@ -5,12 +5,14 @@
 #include "content/browser/renderer_host/gpu_jpeg_decoder.h"
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
 #include "content/browser/gpu/browser_gpu_channel_host_factory.h"
 #include "content/common/gpu/client/gpu_jpeg_decode_accelerator_host.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/common/content_switches.h"
 #include "media/base/video_frame.h"
 
 namespace content {
@@ -21,6 +23,12 @@ bool GpuJpegDecoder::Supported() {
   // platform. Initialize() can do the real platform supporting check but it
   // requires an IPC even for platforms that do not support HW decoder.
   // TODO(kcwu): move this information to GpuInfo.
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableAcceleratedMjpegDecode)) {
+#if defined(OS_CHROMEOS) && defined(ARCH_CPU_X86_FAMILY)

[piman, 2015/06/08 21:25:03]

nit: do you want to move the #ifdef around the switch test? That way you don't
pay for it on other platforms when it's always off.

[kcwu, 2015/06/09 09:05:13]

Done.

+    return true;
+#endif
+  }
   return false;
 }