Revert of Overlays: Remove special casing of primary overlay plane

cc/output/gl_renderer.cc

 // Copyright 2010 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 "cc/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
@@ skipping 3497 matching lines @@
   return gl_->GetGraphicsResetStatusKHR() != GL_NO_ERROR;
 }
 
 void GLRenderer::ScheduleOverlays(DrawingFrame* frame) {
   if (!frame->overlay_list.size())
     return;
 
   ResourceProvider::ResourceIdArray resources;
   OverlayCandidateList& overlays = frame->overlay_list;
   for (const OverlayCandidate& overlay : overlays) {
+    // Skip primary plane.
+    if (overlay.plane_z_order == 0)
+      continue;
+
     unsigned texture_id = 0;
     if (overlay.use_output_surface_for_resource) {
       texture_id = output_surface_->GetOverlayTextureId();
       DCHECK(texture_id);
     } else {
       pending_overlay_resources_.push_back(
           make_scoped_ptr(new ResourceProvider::ScopedReadLockGL(
               resource_provider_, overlay.resource_id)));
       texture_id = pending_overlay_resources_.back()->texture_id();
     }
 
     context_support_->ScheduleOverlayPlane(
         overlay.plane_z_order, overlay.transform, texture_id,
         ToNearestRect(overlay.display_rect), overlay.uv_rect);
   }
 }
 
 }  // namespace cc