Revert of Revert of Move DstCopy on gpu into the GrXferProcessor.

src/gpu/gl/GrGLXferProcessor.h

Index: src/gpu/gl/GrGLXferProcessor.h
diff --git a/src/gpu/gl/GrGLXferProcessor.h b/src/gpu/gl/GrGLXferProcessor.h
index 5c9255903152a6f0bd72019aa976709791fcb57e..7f60f32fe578a6a5591f14a47cf00de8752eb6f3 100644
--- a/src/gpu/gl/GrGLXferProcessor.h
+++ b/src/gpu/gl/GrGLXferProcessor.h
@@ -11,6 +11,7 @@
 #include "GrGLProcessor.h"
 
 class GrGLXPBuilder;
+class GrXferProcessor;
 
 class GrGLXferProcessor {
 public:
@@ -46,16 +47,25 @@
      * This is similar to emitCode() in the base class, except it takes a full shader builder.
      * This allows the effect subclass to emit vertex code.
      */
-    virtual void emitCode(const EmitArgs&) = 0;
+    void emitCode(const EmitArgs&);
 
     /** A GrGLXferProcessor instance can be reused with any GrGLXferProcessor that produces
         the same stage key; this function reads data from a GrGLXferProcessor and uploads any
         uniform variables required  by the shaders created in emitCode(). The GrXferProcessor
         parameter is guaranteed to be of the same type that created this GrGLXferProcessor and
-        to have an identical processor key as the one that created this GrGLXferProcessor.  */
-    virtual void setData(const GrGLProgramDataManager&,
-                         const GrXferProcessor&) = 0;
+        to have an identical processor key as the one that created this GrGLXferProcessor. This
+        function calls onSetData on the subclass of GrGLXferProcessor
+     */
+    void setData(const GrGLProgramDataManager& pdm, const GrXferProcessor& xp);
+
 private:
+    virtual void onEmitCode(const EmitArgs&) = 0;
+
+    virtual void onSetData(const GrGLProgramDataManager&, const GrXferProcessor&) = 0;
+
+    GrGLProgramDataManager::UniformHandle fDstCopyTopLeftUni;
+    GrGLProgramDataManager::UniformHandle fDstCopyScaleUni;
+
     typedef GrGLProcessor INHERITED;
 };
 #endif