Get ReadPixels to work with INT and UNSIGNED_INT format.

gpu/command_buffer/service/framebuffer_manager.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.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_FRAMEBUFFER_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_FRAMEBUFFER_MANAGER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 132 matching lines @@
   void SetDrawBuffers(GLsizei n, const GLenum* bufs);
 
   // If a color buffer is attached to GL_COLOR_ATTACHMENTi, enable that
   // draw buffer for glClear().
   void PrepareDrawBuffersForClear() const;
 
   // Restore draw buffers states that have been changed in
   // PrepareDrawBuffersForClear().
   void RestoreDrawBuffersAfterClear() const;
 
+  // Clear all the active INT or UINT type color buffers to (0, 0, 0, 0).
+  void ClearIntegerBuffers();
+
   // Return true if any draw buffers has an alpha channel.
   bool HasAlphaMRT() const;
 
   // Return false if any two active color attachments have different internal
   // formats.
   bool HasSameInternalFormatsMRT() const;
 
   void OnTextureRefDetached(TextureRef* texture);
-  void OnWillRenderTo() const;
-  void OnDidRenderTo() const;
+
+  // If attachment is 0, apply to all attachments; otherwise, apply only to
+  // the specified attachment.
+  void OnWillRenderTo(GLenum attachment) const;
+  void OnDidRenderTo(GLenum attachment) const;
 
   void set_read_buffer(GLenum read_buffer) {
     read_buffer_ = read_buffer;
   }
 
   GLenum read_buffer() const {
     return read_buffer_;
   }
 
  private:
@@ skipping 164 matching lines @@
 
   scoped_refptr<FramebufferCompletenessCache> framebuffer_combo_complete_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(FramebufferManager);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_FRAMEBUFFER_MANAGER_H_