[Ozone] Fix SingleOnTop issue by checking if the quad is clipped.

cc/output/overlay_unittest.cc

Index: cc/output/overlay_unittest.cc
diff --git a/cc/output/overlay_unittest.cc b/cc/output/overlay_unittest.cc
index 87606f5eb64551848e8e6a40f1ffaba0d54c9ba8..a1fdd63cb2a86fdce9b2a774aada379f3053eb61 100644
--- a/cc/output/overlay_unittest.cc
+++ b/cc/output/overlay_unittest.cc
@@ -36,6 +36,7 @@ const gfx::Size kDisplaySize(256, 256);
 const gfx::Rect kOverlayRect(0, 0, 128, 128);
 const gfx::Rect kOverlayTopLeftRect(0, 0, 64, 64);
 const gfx::Rect kOverlayBottomRightRect(64, 64, 64, 64);
+const gfx::Rect kOverlayClipRect(0, 0, 128, 128);
 const gfx::PointF kUVTopLeft(0.1f, 0.2f);
 const gfx::PointF kUVBottomRight(1.0f, 1.0f);
 const gfx::Transform kNormalTransform =
@@ -66,6 +67,9 @@ class SingleOverlayValidator : public OverlayCandidateValidator {
     ASSERT_EQ(2U, surfaces->size());
 
     OverlayCandidate& candidate = surfaces->back();
+    if (candidate.is_clipped &&
+        !candidate.clip_rect.Contains(candidate.quad_rect_in_target_space))
+      return;
     if (candidate.display_rect.width() == 64) {
       EXPECT_EQ(kOverlayBottomRightRect, candidate.display_rect);
     } else {
@@ -748,6 +752,22 @@ TEST_F(SingleOverlayOnTopTest, RejectNonAxisAlignedTransform) {
   EXPECT_EQ(0U, candidate_list.size());
 }
 
+TEST_F(SingleOverlayOnTopTest, AllowClipped) {
+  scoped_ptr<RenderPass> pass = CreateRenderPass();
+  CreateFullscreenCandidateQuad(resource_provider_.get(),
+                                pass->shared_quad_state_list.back(),
+                                pass.get());
+  pass->shared_quad_state_list.back()->is_clipped = true;
+  pass->shared_quad_state_list.back()->clip_rect = kOverlayClipRect;
+
+  RenderPassList pass_list;
+  pass_list.push_back(pass.Pass());
+  OverlayCandidateList candidate_list;
+  overlay_processor_->ProcessForOverlays(&pass_list, &candidate_list);
+  ASSERT_EQ(1U, pass_list.size());
+  EXPECT_EQ(2U, candidate_list.size());
+}
+
 TEST_F(SingleOverlayOnTopTest, AllowVerticalFlip) {
   gfx::Rect rect = kOverlayRect;
   rect.set_width(rect.width() / 2);