cc: Fix BytesPerPixel issue and refactor.

cc/resources/resource_util.h

Index: cc/resources/resource_util.h
diff --git a/cc/resources/resource_util.h b/cc/resources/resource_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..2708b2ca54f37ac236ea69f37ad82a779f2098d1
--- /dev/null
+++ b/cc/resources/resource_util.h
@@ -0,0 +1,41 @@
+// 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:
+  // Dies with a CRASH() if the size can not be represented as a positive number
+  // of bytes.
+  static size_t CheckedSizeInBytes(const gfx::Size& size,
+                                   ResourceFormat format);
+  // Returns the width in bytes but may overflow or return 0. Only do this for
+  // computing widths for sizes that have already been checked.
+  static size_t UncheckedWidthInBytes(size_t width, ResourceFormat format);
+  static size_t UncheckedWidthInBytesAligned(size_t width,
+                                             ResourceFormat format);
+  // Returns the size in bytes but may overflow or return 0. Only do this for
+  // sizes that have already been checked.
+  static size_t UncheckedSizeInBytes(const gfx::Size& size,
+                                     ResourceFormat format);
+  static size_t UncheckedSizeInBytesAligned(const gfx::Size& size,
+                                            ResourceFormat format);
+  // Return true if the call to size in bytes would return a value that fits in
+  // a size_t.
+  static bool VerifySizeInBytes(const gfx::Size& size, ResourceFormat format);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ResourceUtil);
+};
+
+}  // namespace cc
+
+#endif  // CC_RESOURCES_RESOURCE_UTIL_H_