Make copySurface work in more situations.

src/gpu/gl/GrGLGpu.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLGpu_DEFINED
 #define GrGLGpu_DEFINED
 
@@ skipping 299 matching lines @@
 
     void initFSAASupport();
 
     // determines valid stencil formats
     void initStencilFormats();
 
     // sets a texture unit to use for texture operations other than binding a texture to a program.
     // ensures that such operations don't negatively interact with tracking bound textures.
     void setScratchTextureUnit();
 
-    // bounds is region that may be modified and therefore has to be resolved.
+    // bounds is region that may be modified.
     // nullptr means whole target. Can be an empty rect.
     void flushRenderTarget(GrGLRenderTarget*, const SkIRect* bounds);
+    // Handles cases where a surface will be updated without a call to flushRenderTarget
+    void didWriteToSurface(GrSurface*, const SkIRect* bounds) const;
+
+    // Need not be called if flushRenderTarget is used.
+    void flushViewport(const GrGLIRect&);
 
     void flushStencil(const GrStencilSettings&);
+
+    // rt is used only if useHWAA is true.
     void flushHWAAState(GrRenderTarget* rt, bool useHWAA, bool stencilEnabled);
 
     // helper for onCreateTexture and writeTexturePixels
     enum UploadType {
         kNewTexture_UploadType,    // we are creating a new texture
         kWrite_UploadType,         // we are using TexSubImage2D to copy data to an existing texture
         kTransfer_UploadType,      // we are using a transfer buffer to copy data
     };
     bool uploadTexData(const GrSurfaceDesc& desc,
                        GrGLenum target,
@@ skipping 262 matching lines @@
     } fPLSSetupProgram;
 
     bool fHWPLSEnabled;
     bool fPLSHasBeenUsed;
 
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.
 };
 
 #endif