cc: Remove the software compositing bool from PrepareTextureMailbox

cc/output/renderer_capabilities.cc

 // 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.
 
 #include "cc/output/renderer_capabilities.h"
 
 namespace cc {
 
 RendererCapabilities::RendererCapabilities(ResourceFormat best_texture_format,
-                                           int max_texture_size,
-                                           bool using_shared_memory_resources)
+                                           int max_texture_size)
     : best_texture_format(best_texture_format),
-      max_texture_size(max_texture_size),
-      using_shared_memory_resources(using_shared_memory_resources) {
-}
+      max_texture_size(max_texture_size) {}
 
 RendererCapabilities::RendererCapabilities() = default;
 RendererCapabilities::~RendererCapabilities() = default;
 
 }  // namespace cc