Make copySurface work for texture dsts, return a bool, & add unit test.

include/gpu/GrContext.h

Index: include/gpu/GrContext.h
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index 00a92836c513d6ef9963cc9d3ca925101a2a489a..4245b7fa943cc894cb216f609f1e767116264777 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -278,24 +278,17 @@ public:
      * @param src           the surface to copy from.
      * @param srcRect       the rectangle of the src that should be copied.
      * @param dstPoint      the translation applied when writing the srcRect's pixels to the dst.
-     * @param pixelOpsFlags see PixelOpsFlags enum above. (kUnpremul_PixelOpsFlag is not allowed).
      */
-    void copySurface(GrSurface* dst,
+    bool copySurface(GrSurface* dst,
                      GrSurface* src,
                      const SkIRect& srcRect,
-                     const SkIPoint& dstPoint,
-                     uint32_t pixelOpsFlags = 0);
+                     const SkIPoint& dstPoint);
 
     /** Helper that copies the whole surface but fails when the two surfaces are not identically
         sized. */
     bool copySurface(GrSurface* dst, GrSurface* src) {
-        if (NULL == dst || NULL == src || dst->width() != src->width() ||
-            dst->height() != src->height()) {
-            return false;
-        }
-        this->copySurface(dst, src, SkIRect::MakeWH(dst->width(), dst->height()),
-                          SkIPoint::Make(0,0));
-        return true;
+        return this->copySurface(dst, src, SkIRect::MakeWH(dst->width(), dst->height()),
+                                 SkIPoint::Make(0,0));
     }
 
     /**