cc: make resource keep video buffer format for hardware overlay.

cc/output/overlay_candidate.cc

Index: cc/output/overlay_candidate.cc
diff --git a/cc/output/overlay_candidate.cc b/cc/output/overlay_candidate.cc
index b4210532bc98cdb15b720089cd5637de13b4c915..c6faa50e643392ae66b5567b75abb87f3b5bf395 100644
--- a/cc/output/overlay_candidate.cc
+++ b/cc/output/overlay_candidate.cc
@@ -286,6 +286,10 @@ bool OverlayCandidate::FromStreamVideoQuad(ResourceProvider* resource_provider,
                                            OverlayCandidate* candidate) {
   if (!resource_provider->IsOverlayCandidate(quad->resource_id()))
     return false;
+  candidate->format = resource_provider->GetBufferFormat(quad->resource_id());

[Daniele Castagna, 2017/03/28 02:01:39]

We're not supposed to use the StreamVideoQuad on CrOS.
StreamVideoQuad was added for Android and it is accidentally used in CrOS at the
moment.

crrev.com/2763223003 to limit the usage only to Android.

[dshwang, 2017/03/28 16:42:25]

wow, that's why cros use StreamVideoQuad recently.

By the way, this CL is still valid, because it's not very related to
StreamVideoQuad. It rather makes video_layer_impl set buffer format to resource
for mailbox resource. Without this change, TextureQuad from video cannot know
buffer format. In addition, even though this line isn't used by cros, I think
it's not bad to keep it.

+  if (std::find(std::begin(kOverlayFormats), std::end(kOverlayFormats),
+                candidate->format) == std::end(kOverlayFormats))
+    return false;
   gfx::OverlayTransform overlay_transform = GetOverlayTransform(
       quad->shared_quad_state->quad_to_target_transform, false);
   if (overlay_transform == gfx::OVERLAY_TRANSFORM_INVALID)