Handle compressed textures allocated via TexStorage2D.

gpu/command_buffer/service/gles2_cmd_decoder.h

Index: gpu/command_buffer/service/gles2_cmd_decoder.h
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.h b/gpu/command_buffer/service/gles2_cmd_decoder.h
index 668fbcf540052e4742380af7290e3756ef372fa8..4058f345abe303ee217ad36853535aba7821179a 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.h
@@ -245,6 +245,19 @@ class GPU_EXPORT GLES2Decoder : public base::SupportsWeakPtr<GLES2Decoder>,
                           int width,
                           int height) = 0;
 
+  // Clears a level sub area of a compressed 2D texture.
+  // Returns false if a GL error should be generated.
+  virtual bool ClearCompressedTextureLevel(Texture* texture,
+                                           unsigned target,
+                                           int level,
+                                           unsigned format,
+                                           int width,
+                                           int height) = 0;
+
+  // Indicates whether a given internal format is one for a compressed
+  // texture.
+  virtual bool IsCompressedTextureFormat(unsigned format) = 0;
+
   // Clears a level of a 3D texture.
   // Returns false if a GL error should be generated.
   virtual bool ClearLevel3D(Texture* texture,