Display skips swapping if overlays draw the damage

content/browser/renderer_host/compositor_impl_android.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/compositor_impl_android.h"
 
 #include <android/bitmap.h>
 #include <android/native_window_jni.h>
 
 #include "base/android/jni_android.h"
@@ skipping 76 matching lines @@
             base::Bind(&OutputSurfaceWithoutParent::OnSwapBuffersCompleted,
                        base::Unretained(this))) {
     capabilities_.adjust_deadline_for_parent = false;
     capabilities_.max_frames_pending = kMaxDisplaySwapBuffers;
   }
 
   ~OutputSurfaceWithoutParent() override { compositor_->RemoveObserver(this); }
 
   void SwapBuffers(cc::CompositorFrame* frame) override {
     GetCommandBufferProxy()->SetLatencyInfo(frame->metadata.latency_info);
-    DCHECK(frame->gl_frame_data->sub_buffer_rect ==
-           gfx::Rect(frame->gl_frame_data->size));
-    context_provider_->ContextSupport()->Swap();
-    client_->DidSwapBuffers();
+    // Partial swap is not supported, so if the |sub_buffer_rect| is non-empty
+    // swap the whole buffer. Otherwise, there is no damage, so don't
+    // swap at all.
+    if (!frame->gl_frame_data->sub_buffer_rect.IsEmpty()) {
+      context_provider_->ContextSupport()->Swap();
+      client_->DidSwapBuffers();
+    } else {
+      client_->DidSwapBuffers();
+      OutputSurface::OnSwapBuffersComplete();
+    }
   }
 
   bool BindToClient(cc::OutputSurfaceClient* client) override {
     if (!OutputSurface::BindToClient(client))
       return false;
 
     GetCommandBufferProxy()->SetSwapBuffersCompletionCallback(
         swap_buffers_completion_callback_.callback());
 
     populate_gpu_capabilities_callback_.Run(
@@ skipping 688 matching lines @@
 
 void CompositorImpl::SetNeedsAnimate() {
   needs_animate_ = true;
   if (!host_->visible())
     return;
 
   host_->SetNeedsAnimate();
 }
 
 }  // namespace content