Add shared bitmap managers for browser and renderer processes.

cc/resources/shared_bitmap.cc

 // Copyright 2013 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/resources/shared_bitmap.h"
 
+#include "base/rand_util.h"
+
 namespace cc {
 
 SharedBitmap::SharedBitmap(
     base::SharedMemory* memory,
     const SharedBitmapId& id,
     const base::Callback<void(SharedBitmap*)>& free_callback)
     : memory_(memory), id_(id), free_callback_(free_callback) {}
 
 SharedBitmap::~SharedBitmap() { free_callback_.Run(this); }
 
+// static
+size_t SharedBitmap::GetSizeInBytes(const gfx::Size& size) {
+  return size.GetArea() * 4;
+}
+
+// static
+SharedBitmapId SharedBitmap::GenerateId() {
+  SharedBitmapId id;
+  base::RandBytes(id.name, sizeof id.name);

[danakj, 2014/01/30 22:59:01]

nit: sizeof(id.name)

+  return id;
+}
+
 }  // namespace cc