Force use of and cache render surface.

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 <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 971 matching lines @@
   // cause device_quad to become clipped. To our knowledge this scenario does
   // not need to be handled differently than the unclipped case.
   return local_quad;
 }
 
 const TileDrawQuad* GLRenderer::CanPassBeDrawnDirectly(const RenderPass* pass) {
   // Can only collapse a single tile quad.
   if (pass->quad_list.size() != 1)
     return nullptr;
   // If we need copy requests, then render pass has to exist.
-  if (!pass->copy_requests.empty())
+  if (!pass->copy_requests.empty() || pass->force_render_surface)

[reveman, 2017/05/10 13:06:17]

I'm not sure we want to avoid this optimization. It's still useful to skip the
intermediate texture when not needed. I think it would be better to leave this
as is. Wdyt?

[wutao, 2017/05/11 19:36:34]

Agree. Removed.

     return nullptr;
 
   const DrawQuad* quad = *pass->quad_list.BackToFrontBegin();
   // Hack: this could be supported by concatenating transforms, but
   // in practice if there is one quad, it is at the origin of the render pass
   // and has the same size as the pass.
   if (!quad->shared_quad_state->quad_to_target_transform.IsIdentity() ||
       quad->rect != pass->output_rect)
     return nullptr;
   // The quad is expected to be the entire layer so that AA edges are correct.
@@ skipping 2605 matching lines @@
     return;
 
   // Report GPU overdraw as a percentage of |max_result|.
   TRACE_COUNTER1(
       TRACE_DISABLED_BY_DEFAULT("cc.debug.overdraw"), "GPU Overdraw",
       (std::accumulate(overdraw->begin(), overdraw->end(), 0) * 100) /
           max_result);
 }
 
 }  // namespace cc