Fix glTexSubImage2D for non-32bpp formats.

cc/texture.h

 // Copyright 2012 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 CCTexture_h
 #define CCTexture_h
 
 #include "IntSize.h"
 #include "cc/resource_provider.h"
 #include "third_party/khronos/GLES2/gl2.h"
@@ skipping 10 matching lines @@
 
     CCResourceProvider::ResourceId id() const { return m_id; }
     const IntSize& size() const { return m_size; }
     GLenum format() const { return m_format; }
 
     void setId(CCResourceProvider::ResourceId id) { m_id = id; }
     void setDimensions(const IntSize&, GLenum format);
 
     size_t bytes() const;
 
+    static size_t bytesPerPixel(GLenum format);
     static size_t memorySizeBytes(const IntSize&, GLenum format);
 
 private:
     CCResourceProvider::ResourceId m_id;
     IntSize m_size;
     GLenum m_format;
 };
 
 }
 
 #endif