Add standard way to indicate GM is GPU-only.

gm/dcshader.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.
  */
 
 #include "gm.h"
 #if SK_SUPPORT_GPU
@@ skipping 230 matching lines @@
         fPrims.push_back(SkNEW(DRRect));
         fPrims.push_back(SkNEW(Path));
         fPrims.push_back(SkNEW(Points(SkCanvas::kPoints_PointMode)));
         fPrims.push_back(SkNEW(Points(SkCanvas::kLines_PointMode)));
         fPrims.push_back(SkNEW(Points(SkCanvas::kPolygon_PointMode)));
         fPrims.push_back(SkNEW(Text));
         fPrims.push_back(SkNEW(BmpText));
     }
 
     void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        // This GM exists to test a specific feature of the GPU backend. It does not work with the
+        // sw rasterizer, tile modes, etc.
+        if (NULL == canvas->getGrContext()) {
+            this->drawGpuOnlyMessage(canvas);
+            return;
+        }
         SkPaint paint;
         SkTArray<SkMatrix> devMats;
         devMats.push_back().reset();
         devMats.push_back().setRotate(45, 500, 500);
         devMats.push_back().setRotate(-30, 200, 200);
         devMats.back().setPerspX(-SK_Scalar1 / 2000);
         devMats.back().setPerspY(SK_Scalar1 / 1000);
 
 
         SkTArray<SkMatrix> viewMats;
@@ skipping 44 matching lines @@
     };
 
     SkTArray<Prim*> fPrims;
 
     typedef GM INHERITED;
 };
 
 DEF_GM( return SkNEW(DCShaderGM); )
 }
 #endif