Revert "Revert "Use SCANOUT_* usage in GpuMemoryBufferVideoFramePool""

This reverts commit 09ef7a92.

Reason for revert: the original revert did not fix ProcessManagerBrowserTest.NestedURLNavigationsToExtensionBlocked failing: https://bugs.chromium.org/p/chromium/issues/detail?id=806684#c8 

Original change's description:
> 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/890978
> Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
> Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#532344}

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

Change-Id: I92a0379b36cdc6b21bf609ab69a467acbad23c9e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: b/71837407
Reviewed-on: https://chromium-review.googlesource.com/891718Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532513}

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::GPU_READ_CPU_READ_WRITE);
+        gfx::BufferUsage::SCANOUT_CPU_READ_WRITE);
 
     unsigned texture_target = gpu_factories_->ImageTextureTarget(buffer_format);
     gles2->GenTextures(1, &plane_resource.texture_id);