Overlays: Remove special casing of primary overlay plane

cc/output/overlay_strategy_common.cc

Index: cc/output/overlay_strategy_common.cc
diff --git a/cc/output/overlay_strategy_common.cc b/cc/output/overlay_strategy_common.cc
index 5048b1a1c074b8e92a07bfc72ef4c65334d47c87..36728dd9baf7ba48ba51dcb671f055d35ea612f2 100644
--- a/cc/output/overlay_strategy_common.cc
+++ b/cc/output/overlay_strategy_common.cc
@@ -34,12 +34,6 @@ bool OverlayStrategyCommon::Attempt(RenderPassList* render_passes_in_draw_order,
   RenderPass* root_render_pass = render_passes_in_draw_order->back();
   DCHECK(root_render_pass);
 
-  // Add our primary surface.
-  OverlayCandidate main_image;
-  main_image.display_rect = gfx::RectF(root_render_pass->output_rect);
-  DCHECK(candidate_list->empty());
-  candidate_list->push_back(main_image);
-
   bool created_overlay = false;
   QuadList& quad_list = root_render_pass->quad_list;
   for (auto it = quad_list.begin(); it != quad_list.end();) {
@@ -64,11 +58,6 @@ bool OverlayStrategyCommon::Attempt(RenderPassList* render_passes_in_draw_order,
     }
   }
 
-  if (!created_overlay) {
-    DCHECK_EQ(1u, candidate_list->size());
-    candidate_list->clear();
-  }
-
   return created_overlay;
 }