Save and temp dst and src FBO on GrGLGpu and use the temp FBOs for copySurface if needed.

src/gpu/gl/GrGLGpu.h

Index: src/gpu/gl/GrGLGpu.h
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index c5103ebb1159bde79bdb1c4c8294bdccc8ae713a..7eda0143442ea12d92f28e2d277bb28430f13707 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -283,7 +283,15 @@ private:
     bool createRenderTargetObjects(const GrSurfaceDesc&, bool budgeted, GrGLuint texID, 
                                    GrGLRenderTarget::IDDesc*);
 
-    GrGLuint bindSurfaceAsFBO(GrSurface* surface, GrGLenum fboTarget, GrGLIRect* viewport);
+    enum TempFBOTarget {
+        kSrc_TempFBOTarget,
+        kDst_TempFBOTarget
+    };
+
+    GrGLuint bindSurfaceAsFBO(GrSurface* surface, GrGLenum fboTarget, GrGLIRect* viewport,
+                              TempFBOTarget tempFBOTarget);
+
+    void unbindTextureFromFBO(GrGLenum fboTarget);
 
     GrGLContext fGLContext;
 
@@ -303,6 +311,9 @@ private:
         kUnknown_TriState
     };
 
+    GrGLuint                    fTempSrcFBOID;
+    GrGLuint                    fTempDstFBOID;
+
     // last scissor / viewport scissor state seen by the GL.
     struct {
         TriState    fEnabled;