Display skips swapping if overlays draw the damage

cc/output/direct_renderer.cc

Index: cc/output/direct_renderer.cc
diff --git a/cc/output/direct_renderer.cc b/cc/output/direct_renderer.cc
index 4acd9c142ad5b3ef95638a574270d774b3d0a935..2a1a8b95dd8d0530cac4e5f9e06e83ebb824dd04 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -188,11 +188,12 @@ void DirectRenderer::DecideRenderPassAllocationsForFrame(
   }
 }
 
-void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
-                               float device_scale_factor,
-                               const gfx::Rect& device_viewport_rect,
-                               const gfx::Rect& device_clip_rect,
-                               bool disable_picture_quad_image_filtering) {
+DrawFrameResult DirectRenderer::DrawFrame(
+    RenderPassList* render_passes_in_draw_order,
+    float device_scale_factor,
+    const gfx::Rect& device_viewport_rect,
+    const gfx::Rect& device_clip_rect,
+    bool disable_picture_quad_image_filtering) {
   TRACE_EVENT0("cc", "DirectRenderer::DrawFrame");
   UMA_HISTOGRAM_COUNTS(
       "Renderer4.renderPassCount",
@@ -205,9 +206,7 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
   DrawingFrame frame;
   frame.render_passes_in_draw_order = render_passes_in_draw_order;
   frame.root_render_pass = root_render_pass;
-  frame.root_damage_rect = Capabilities().using_partial_swap
-                               ? root_render_pass->damage_rect
-                               : root_render_pass->output_rect;
+  frame.root_damage_rect = root_render_pass->damage_rect;
   frame.root_damage_rect.Union(overlay_processor_->GetAndResetOverlayDamage());
   frame.root_damage_rect.Intersect(gfx::Rect(device_viewport_rect.size()));
   frame.device_viewport_rect = device_viewport_rect;
@@ -248,16 +247,22 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
       break;
     }
   }
+  gfx::Rect damage_rect_minus_overlays = frame.root_damage_rect;
   if (!has_copy_requests) {
     overlay_processor_->ProcessForOverlays(
         resource_provider_, render_passes_in_draw_order, &frame.overlay_list,
-        &frame.ca_layer_overlay_list, &frame.root_damage_rect);
+        &frame.ca_layer_overlay_list, &damage_rect_minus_overlays);
+    frame.root_damage_rect = Capabilities().using_partial_swap
+                                 ? damage_rect_minus_overlays
+                                 : root_render_pass->output_rect;
   }
 
   // If all damage is being drawn with overlays or CALayers then skip drawing
   // the render passes.
-  if (frame.root_damage_rect.IsEmpty() && !has_copy_requests) {
+  DrawFrameResult draw_result = DrawFrameResult::DID_DRAW;
+  if (damage_rect_minus_overlays.IsEmpty() && !has_copy_requests) {
     BindFramebufferToOutputSurface(&frame);
+    draw_result = DrawFrameResult::DAMAGE_DRAWN_BY_OVERLAYS;
   } else {
     for (const auto& pass : *render_passes_in_draw_order) {
       DrawRenderPass(&frame, pass.get());
@@ -275,6 +280,7 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
   }
   FinishDrawingFrame(&frame);
   render_passes_in_draw_order->clear();
+  return draw_result;
 }
 
 gfx::Rect DirectRenderer::ComputeScissorRectForRenderPass(