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

ui/ozone/public/overlay_candidates_ozone.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_OZONE_PUBLIC_OVERLAY_CANDIDATES_OZONE_H_
 #define UI_OZONE_PUBLIC_OVERLAY_CANDIDATES_OZONE_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 17 matching lines @@
     // Format of the buffer to composite.
     gfx::BufferFormat format = gfx::BufferFormat::BGRA_8888;
     // Size of the buffer, in pixels.
     gfx::Size buffer_size;
     // Rect on the display to position the overlay to. Input rectangle may
     // not have integer coordinates, but when accepting for overlay, must
     // be modified by CheckOverlaySupport to output integer values.
     gfx::RectF display_rect;
     // Crop within the buffer to be placed inside |display_rect|.
     gfx::RectF crop_rect;
+    // Quad geometry rect after applying the quad_transform().
+    gfx::Rect quad_rect_in_target_space;
+    // Clip rect in the target content space after composition.
+    gfx::Rect clip_rect;
+    // If the quad is clipped after composition.
+    bool is_clipped;
     // Stacking order of the overlay plane relative to the main surface,
     // which is 0. Signed to allow for "underlays".
     int plane_z_order = 0;
 
     // To be modified by the implementer if this candidate can go into
     // an overlay.
     bool overlay_handled = false;
   };
 
   typedef std::vector<OverlaySurfaceCandidate> OverlaySurfaceCandidateList;
 
   // A list of possible overlay candidates is presented to this function.
   // The expected result is that those candidates that can be in a separate
   // plane are marked with |overlay_handled| set to true, otherwise they are
   // to be traditionally composited. When setting |overlay_handled| to true,
   // the implementation must also snap |display_rect| to integer coordinates
   // if necessary.
   virtual void CheckOverlaySupport(OverlaySurfaceCandidateList* surfaces);
 
   virtual ~OverlayCandidatesOzone();
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PUBLIC_OVERLAY_CANDIDATES_OZONE_H_