Add GL_EXT_unpack_subimage support to command buffer client code.

gpu/command_buffer/common/gles2_cmd_utils.h

 // Copyright (c) 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.
 
 // This file is here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 #define GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 
@@ skipping 85 matching lines @@
   }
 
   void set_num_shader_binary_formats(int num_shader_binary_formats) {
     num_shader_binary_formats_ = num_shader_binary_formats;
   }
 
   // Gets the number of values a particular id will return when a glGet
   // function is called. If 0 is returned the id is invalid.
   int GLGetNumValuesReturned(int id) const;
 
+  // Computes the size of a single group of elements from a format and type pair
+  static uint32 ComputeImageGroupSize(int format, int type);
+
+  // Computes the size of an image row including alignment padding
+  static bool ComputeImagePaddedRowSize(
+    int width, int format, int type, int unpack_alignment,
+    uint32* padded_row_size);
+
   // Computes the size of image data for TexImage2D and TexSubImage2D.
-  static bool ComputeImageDataSize(
+  // Optionally the unpadded and padded row sizes can be returned. If height < 2
+  // then the padded_row_size will be the same as the unpadded_row_size since
+  // padding is not necessary.
+  static bool ComputeImageDataSizes(
     int width, int height, int format, int type, int unpack_alignment,
-    uint32* size);
+    uint32* size, uint32* unpadded_row_size, uint32* padded_row_size);
 
   static size_t RenderbufferBytesPerPixel(int format);
 
   static uint32 GetGLDataTypeSizeForUniforms(int type);
 
   static size_t GetGLTypeSizeForTexturesAndBuffers(uint32 type);
 
   static uint32 GLErrorToErrorBit(uint32 gl_error);
 
   static uint32 GLErrorBitToGLError(uint32 error_bit);
@@ skipping 45 matching lines @@
   bool buffer_preserved_;
   bool share_resources_;
   bool bind_generates_resource_;
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_