cc: Fix BytesPerPixel issue and refactor.

cc/resources/resource_util.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_RESOURCES_RESOURCE_UTIL_H_
+#define CC_RESOURCES_RESOURCE_UTIL_H_
+
+#include "cc/base/cc_export.h"
+#include "cc/resources/resource_format.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace cc {
+
+class CC_EXPORT ResourceUtil {
+ public:
+  // Return true if the call to SizeInBytes would return a value
+  // that fits in a size_t.
+  static bool VerifySizeInBytes(const gfx::Size& size, ResourceFormat format);
+  static size_t CheckedSizeInBytes(const gfx::Size& size,
+                                   ResourceFormat format);
+  static size_t WidthInBytes(size_t width, ResourceFormat format);
+  static size_t SizeInBytes(const gfx::Size& size, ResourceFormat format);
+  static size_t WidthInBytesAligned(size_t width, ResourceFormat format);
+  static size_t SizeInBytesAligned(const gfx::Size& size,
+                                   ResourceFormat format);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ResourceUtil);
+};
+
+}  // namespace cc
+
+#endif  // CC_RESOURCES_RESOURCE_UTIL_H_