cc: Remove the software compositing bool from PrepareTextureMailbox

cc/output/renderer_capabilities.h

 // Copyright 2015 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.
 
 #ifndef CC_OUTPUT_RENDERER_CAPABILITIES_H_
 #define CC_OUTPUT_RENDERER_CAPABILITIES_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/resources/resource_format.h"
 
 namespace cc {
 
 // Represents the set of capabilities that a particular Renderer has.
 struct CC_EXPORT RendererCapabilities {
   RendererCapabilities(ResourceFormat best_texture_format,
-                       int max_texture_size,
-                       bool using_shared_memory_resources);
+                       int max_texture_size);
 
   RendererCapabilities();
   ~RendererCapabilities();
 
   // Duplicate any modification to this list to RendererCapabilitiesImpl.
   ResourceFormat best_texture_format;
   int max_texture_size;
-  bool using_shared_memory_resources;
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_RENDERER_CAPABILITIES_H_