Move copy-surface-as-draw fallback to GrGLGpu.

src/gpu/GrDrawTarget.h

Index: src/gpu/GrDrawTarget.h
diff --git a/src/gpu/GrDrawTarget.h b/src/gpu/GrDrawTarget.h
index 84f7eb2197a4aa736aabba9847b9ba5b08ab5518..0157354f88ec02891ca476f08f64f2b534d030a0 100644
--- a/src/gpu/GrDrawTarget.h
+++ b/src/gpu/GrDrawTarget.h
@@ -178,25 +178,15 @@ public:
      * copied are specified by srcRect. They are copied to a rect of the same
      * size in dst with top left at dstPoint. If the src rect is clipped by the
      * src bounds then  pixel values in the dst rect corresponding to area clipped
-     * by the src rect are not overwritten. This method can fail and return false
+     * by the src rect are not overwritten. This method is not guaranteed to succeed
      * depending on the type of surface, configs, etc, and the backend-specific
-     * limitations. If rect is clipped out entirely by the src or dst bounds then
-     * true is returned since there is no actual copy necessary to succeed.
+     * limitations.
      */
-    bool copySurface(GrSurface* dst,
+    void copySurface(GrSurface* dst,
                      GrSurface* src,
                      const SkIRect& srcRect,
                      const SkIPoint& dstPoint);
     /**
-     * Function that determines whether a copySurface call would succeed without actually
-     * performing the copy.
-     */
-    bool canCopySurface(const GrSurface* dst,
-                        const GrSurface* src,
-                        const SkIRect& srcRect,
-                        const SkIPoint& dstPoint);
-
-    /**
      * Release any resources that are cached but not currently in use. This
      * is intended to give an application some recourse when resources are low.
      */