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

ui/ozone/platform/dri/test/mock_dri_wrapper.cc

 // 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.
 
 #include "ui/ozone/platform/dri/test/mock_dri_wrapper.h"
 
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
 #include "base/logging.h"
@@ skipping 51 matching lines @@
                                std::vector<uint32_t> crtcs,
                                size_t planes_per_crtc)
     : DriWrapper("", use_sync_flips),
       get_crtc_call_count_(0),
       set_crtc_call_count_(0),
       restore_crtc_call_count_(0),
       add_framebuffer_call_count_(0),
       remove_framebuffer_call_count_(0),
       page_flip_call_count_(0),
       overlay_flip_call_count_(0),
+      overlay_clear_call_count_(0),
       set_crtc_expectation_(true),
       add_framebuffer_expectation_(true),
       page_flip_expectation_(true),
       create_dumb_buffer_expectation_(true),
       current_framebuffer_(0) {
   fd_ = fd;
   plane_manager_.reset(
       new MockHardwareDisplayPlaneManager(this, crtcs, planes_per_crtc));
 }
 
@@ skipping 64 matching lines @@
   }
 
   return page_flip_expectation_;
 }
 
 bool MockDriWrapper::PageFlipOverlay(uint32_t crtc_id,
                                      uint32_t framebuffer,
                                      const gfx::Rect& location,
                                      const gfx::Rect& source,
                                      int overlay_plane) {
+  if (!framebuffer)
+    overlay_clear_call_count_++;
   overlay_flip_call_count_++;
   return true;
 }
 
 ScopedDrmPropertyPtr MockDriWrapper::GetProperty(drmModeConnector* connector,
                                                  const char* name) {
   return ScopedDrmPropertyPtr(DrmAllocator<drmModePropertyRes>());
 }
 
 bool MockDriWrapper::SetProperty(uint32_t connector_id,
@@ skipping 48 matching lines @@
 
 void MockDriWrapper::RunCallbacks() {
   while (!callbacks_.empty()) {
     PageFlipCallback callback = callbacks_.front();
     callbacks_.pop();
     callback.Run(0, 0, 0);
   }
 }
 
 }  // namespace ui