Add standard way to indicate GM is GPU-only.

gm/yuvtorgbeffect.cpp

 
 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 // This test only works with the GPU backend.
 
@@ skipping 48 matching lines @@
         }
     }
 
     void onDraw(SkCanvas* canvas) SK_OVERRIDE {
         GrRenderTarget* rt = canvas->internal_private_accessTopLayerRenderTarget();
         if (NULL == rt) {
             return;
         }
         GrContext* context = rt->getContext();
         if (NULL == context) {
+            this->drawGpuOnlyMessage(canvas);
             return;
         }
 
         GrTestTarget tt;
         context->getTestTarget(&tt);
         if (NULL == tt.target()) {
             SkDEBUGFAIL("Couldn't get Gr test target.");
             return;
         }
 
@@ skipping 45 matching lines @@
 private:
     SkBitmap fBmp[3];
 
     typedef GM INHERITED;
 };
 
 DEF_GM( return SkNEW(YUVtoRGBEffect); )
 }
 
 #endif