Revert "Use SCANOUT_* usage in GpuMemoryBufferVideoFramePool"

This reverts commit b6486594.

Reason for revert: speculative revert for fixing browser_tests
failure on Win (32) Tests bot.

ProcessManagerBrowserTest.NestedURLNavigationsToExtensionBlocked started to fail
continuously after the CL. I'm not fully confident of the 
relationship between the failure and this change, but trying to
revert to see if it helps. 


Original change's description:
> Use SCANOUT_* usage in GpuMemoryBufferVideoFramePool
> 
> Currently GpuMemoryBufferVideoFramePool allocates buffers with
> GPU_READ_CPU_READ_WRITE usage. This means these buffers won't be used for
> scanout (no fb added on CrOS).
> 
> This CL simply changes the usage used when allocating buffers to
> SCANOUT_CPU_READ_WRITE, in this way this buffers will be created for
> scanout, if possible.
> 
> Note that SCANOUT implies GPU_READ, meaning that in case the allocation
> of the buffer for scanout will fail, the buffers will be allocated
> exactly as they'd be if GPU_READ_CPU_READ_WRITE were used instead.
> 
> Bug: b/71837407
> Change-Id: I3a03daf721f1cc04038a4f6f91985b5affe2a276
> Reviewed-on: https://chromium-review.googlesource.com/884401
> Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
> Reviewed-by: Miguel Casas <mcasas@chromium.org>
> Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#532286}

TBR=dalecurtis@chromium.org,mcasas@chromium.org,dcastagna@chromium.org,hoegsberg@chromium.org,ddavenport@chromium.org

Change-Id: I13c479543ac53694f6f413c83aa15481e9c80c53
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: b/71837407
Reviewed-on: https://chromium-review.googlesource.com/890978Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532344}

media/video/gpu_memory_buffer_video_frame_pool.cc

@@ -908,7 +908,7 @@ GpuMemoryBufferVideoFramePool::PoolImpl::GetOrCreateFrameResources(
     const gfx::BufferFormat buffer_format = GpuMemoryBufferFormat(format, i);
     plane_resource.gpu_memory_buffer = gpu_factories_->CreateGpuMemoryBuffer(
         plane_resource.size, buffer_format,
-        gfx::BufferUsage::SCANOUT_CPU_READ_WRITE);
+        gfx::BufferUsage::GPU_READ_CPU_READ_WRITE);
 
     unsigned texture_target = gpu_factories_->ImageTextureTarget(buffer_format);
     gles2->GenTextures(1, &plane_resource.texture_id);