media: Declare GpuMojoMediaClient::gpu_memory_buffer_factory_ for ChromeOS only

GpuMojoMediaClient::gpu_memory_buffer_factory_ is guarded by
BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION), however it is only used in
the ChromeOS specific code path.

This results in the following error if standard Chrome is built with
use_vaapi=true or use_v4l2_codec=true on Linux:

In file included from ../../media/mojo/services/gpu_mojo_media_client.cc:5:
../../media/mojo/services/gpu_mojo_media_client.h:77:38: error:
    private field 'gpu_memory_buffer_factory_' is not used
    [-Werror,-Wunused-private-field]
  gpu::GpuMemoryBufferFactory* const gpu_memory_buffer_factory_;

Add "defined(OS_CHROMEOS)" to the #ifs that guard the field declaration
and assignment in the constructor to match the code path that uses it.

Test: compile and run media_unittests with use_vaapi=true on Linux
Test: compile and run media_unittests simplechrome (chromeos-amd64-generic-rel)
Change-Id: Ic621272e06d4e5457572f1eadbd9f549638446a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898280Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Jeffrey Kardatzke <jkardatzke@google.com>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713143}

media/mojo/services/gpu_mojo_media_client.cc

@@ -119,9 +119,9 @@ GpuMojoMediaClient::GpuMojoMediaClient(
       gpu_task_runner_(std::move(gpu_task_runner)),
       media_gpu_channel_manager_(std::move(media_gpu_channel_manager)),
       android_overlay_factory_cb_(std::move(android_overlay_factory_cb)),
-#if BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
+#if defined(OS_CHROMEOS) && BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
       gpu_memory_buffer_factory_(gpu_memory_buffer_factory),
-#endif  // BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
+#endif  // defined(OS_CHROMEOS) && BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
       cdm_proxy_factory_cb_(std::move(cdm_proxy_factory_cb)) {
 }
 

media/mojo/services/gpu_mojo_media_client.h

@@ -72,10 +72,10 @@ class GpuMojoMediaClient : public MojoMediaClient {
   scoped_refptr<base::SingleThreadTaskRunner> gpu_task_runner_;
   base::WeakPtr<MediaGpuChannelManager> media_gpu_channel_manager_;
   AndroidOverlayMojoFactoryCB android_overlay_factory_cb_;
-#if BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
+#if defined(OS_CHROMEOS) && BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
   // Indirectly owned by GpuChildThread.
   gpu::GpuMemoryBufferFactory* const gpu_memory_buffer_factory_;
-#endif  // BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
+#endif  // defined(OS_CHROMEOS) && BUILDFLAG(USE_CHROMEOS_MEDIA_ACCELERATION)
   CdmProxyFactoryCB cdm_proxy_factory_cb_;
 #if defined(OS_WIN)
   base::Optional<SupportedVideoDecoderConfigs> d3d11_supported_configs_;