ResourceProvider should be able to avoid allocating immutable textures.

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 598 matching lines @@
 
   int top, right, bottom, left;
   quad->background_filters.GetOutsets(&top, &right, &bottom, &left);
   window_rect.Inset(-left, -top, -right, -bottom);
 
   window_rect.Intersect(
       MoveFromDrawToWindowSpace(frame->current_render_pass->output_rect));
 
   scoped_ptr<ScopedResource> device_background_texture =
       ScopedResource::create(resource_provider_);
-  if (!device_background_texture->Allocate(window_rect.size(),
-                                           ResourceProvider::TextureUsageAny,
-                                           RGBA_8888)) {
+  // The TextureUsageFramebuffer hint makes ResourceProvider to avoid immutable

[danakj, 2013/11/21 00:20:41]

s/to avoid/avoid/

+  // storage allocation (texStorage2DEXT) for this texture. copyTexImage2D fails
+  // when called on a texture having immutable storage.
+  if (!device_background_texture->Allocate(
+           window_rect.size(),
+           ResourceProvider::TextureUsageFramebuffer,
+           RGBA_8888)) {
     return scoped_ptr<ScopedResource>();
   } else {
     ResourceProvider::ScopedWriteLockGL lock(resource_provider_,
                                              device_background_texture->id());
     GetFramebufferTexture(lock.texture_id(),
                           device_background_texture->format(),
                           window_rect);
   }
 
   skia::RefPtr<SkImageFilter> filter = RenderSurfaceFilters::BuildImageFilter(
@@ skipping 2316 matching lines @@
   // The Skia GPU backend requires a stencil buffer.  See ReinitializeGrCanvas
   // implementation.
   return gr_context_ && context_->getContextAttributes().stencil;
 }
 
 bool GLRenderer::IsContextLost() {
   return output_surface_->context_provider()->IsContextLost();
 }
 
 }  // namespace cc