Fix V4L2VideoEncodeAccelerator is not enabled in GN build

media/gpu/ipc/service/gpu_video_encode_accelerator.h

Index: media/gpu/ipc/service/gpu_video_encode_accelerator.h
diff --git a/media/gpu/ipc/service/gpu_video_encode_accelerator.h b/media/gpu/ipc/service/gpu_video_encode_accelerator.h
index 9b86c08d2a38d39a2a2193346a5799147a07e072..4e00f27bd6f2d14d84fa8d8e35ceb757ba640f43 100644
--- a/media/gpu/ipc/service/gpu_video_encode_accelerator.h
+++ b/media/gpu/ipc/service/gpu_video_encode_accelerator.h
@@ -80,7 +80,8 @@ class GpuVideoEncodeAccelerator
   // platform.
   static std::vector<CreateVEAFp> CreateVEAFps(
       const gpu::GpuPreferences& gpu_preferences);
-#if defined(OS_CHROMEOS) && defined(USE_V4L2_CODEC)
+#if defined(OS_CHROMEOS) && (defined(ARCH_CPU_ARMEL) || \
+                             (defined(USE_OZONE) && defined(USE_V4L2_CODEC)))

[wuchengli, 2016/07/12 11:39:51]

Why do we need ozone? https://codereview.chromium.org/834113004 does the same. I
don't understand the relationship between having ozone and having v4l2 devices.
Don't all x86 have ozone?

This is not related to this CL. So if we don't need ozone, we can remove it in
another CL.

[ilja, 2016/07/12 21:25:02]

All shipping boards except for tegra have ozone right now. But I think generic
builds might not have it. Of course that config is becoming less and less
relevant these days.

[wuchengli, 2016/07/13 02:24:10]

I looked at the git history and old chromium issues. I'm sure USE_OZONE is not
needed here.

[henryhsu, 2016/07/13 03:29:59]

will remove in another cl

   static std::unique_ptr<VideoEncodeAccelerator> CreateV4L2VEA();
 #endif
 #if defined(OS_CHROMEOS) && defined(ARCH_CPU_X86_FAMILY)