gpu: Use a rectangle to keep track of the cleared area of each texture level.

gpu/command_buffer/service/gles2_cmd_decoder.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 contains the GLES2Decoder class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_
 
 #include <vector>
@@ skipping 192 matching lines @@
       AsyncPixelTransferManager* manager) = 0;
 
   // Get the service texture ID corresponding to a client texture ID.
   // If no such record is found then return false.
   virtual bool GetServiceTextureId(uint32 client_texture_id,
                                    uint32* service_texture_id);
 
   // Provides detail about a lost context if one occurred.
   virtual error::ContextLostReason GetContextLostReason() = 0;
 
-  // Clears a level of a texture
+  // Clears a level sub area of a texture
   // Returns false if a GL error should be generated.
-  virtual bool ClearLevel(
-      Texture* texture,
-      unsigned target,
-      int level,
-      unsigned internal_format,
-      unsigned format,
-      unsigned type,
-      int width,
-      int height,
-      bool is_texture_immutable) = 0;
+  virtual bool ClearLevel(Texture* texture,
+                          unsigned target,
+                          int level,
+                          unsigned format,
+                          unsigned type,
+                          int xoffset,
+                          int yoffset,
+                          int width,
+                          int height) = 0;
 
   virtual ErrorState* GetErrorState() = 0;
 
   // A callback for messages from the decoder.
   virtual void SetShaderCacheCallback(const ShaderCacheCallback& callback) = 0;
 
   // Sets the callback for waiting on a sync point. The callback returns the
   // scheduling status (i.e. true if the channel is still scheduled).
   virtual void SetWaitSyncPointCallback(
       const WaitSyncPointCallback& callback) = 0;
@@ skipping 30 matching lines @@
   bool log_commands_;
   bool unsafe_es3_apis_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(GLES2Decoder);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_