ozone: fix HDPMLegacy - do the PF after overlays, also clear old overlays

ui/ozone/platform/dri/test/mock_dri_wrapper.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_PLATFORM_DRI_TEST_MOCK_DRI_WRAPPER_H_
 #define UI_OZONE_PLATFORM_DRI_TEST_MOCK_DRI_WRAPPER_H_
 
 #include <queue>
 #include <vector>
 
@@ skipping 19 matching lines @@
   int get_set_crtc_call_count() const { return set_crtc_call_count_; }
   int get_restore_crtc_call_count() const { return restore_crtc_call_count_; }
   int get_add_framebuffer_call_count() const {
     return add_framebuffer_call_count_;
   }
   int get_remove_framebuffer_call_count() const {
     return remove_framebuffer_call_count_;
   }
   int get_page_flip_call_count() const { return page_flip_call_count_; }
   int get_overlay_flip_call_count() const { return overlay_flip_call_count_; }
+  int get_overlay_clear_call_count() const { return overlay_clear_call_count_; }
   void fail_init() { fd_ = -1; }
   void set_set_crtc_expectation(bool state) { set_crtc_expectation_ = state; }
   void set_page_flip_expectation(bool state) { page_flip_expectation_ = state; }
   void set_add_framebuffer_expectation(bool state) {
     add_framebuffer_expectation_ = state;
   }
   void set_create_dumb_buffer_expectation(bool state) {
     create_dumb_buffer_expectation_ = state;
   }
 
@@ skipping 53 matching lines @@
                          void* pixels) override;
 
  private:
   int get_crtc_call_count_;
   int set_crtc_call_count_;
   int restore_crtc_call_count_;
   int add_framebuffer_call_count_;
   int remove_framebuffer_call_count_;
   int page_flip_call_count_;
   int overlay_flip_call_count_;
+  int overlay_clear_call_count_;
 
   bool set_crtc_expectation_;
   bool add_framebuffer_expectation_;
   bool page_flip_expectation_;
   bool create_dumb_buffer_expectation_;
 
   uint32_t current_framebuffer_;
 
   std::vector<skia::RefPtr<SkSurface> > buffers_;
 
   std::queue<PageFlipCallback> callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(MockDriWrapper);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_TEST_MOCK_DRI_WRAPPER_H_