Support using OpenGL ES context on desktop

dm/DMGpuGMTask.h

Index: dm/DMGpuGMTask.h
diff --git a/dm/DMGpuGMTask.h b/dm/DMGpuGMTask.h
index 6e076ecad45b949bf6dd8b007f3e460c97fba574..9a90989b26410401e9093a78cc0b44fcf8fb1a77 100644
--- a/dm/DMGpuGMTask.h
+++ b/dm/DMGpuGMTask.h
@@ -23,6 +23,7 @@ public:
               const Expectations&,
               skiagm::GMRegistry::Factory,
               GrContextFactory::GLContextType,
+              GrGLStandard forcedGpuApi,
               int sampleCount);
 
     virtual void draw(GrContextFactory*) SK_OVERRIDE;
@@ -34,6 +35,7 @@ private:
     const SkString fName;
     const Expectations& fExpectations;
     const GrContextFactory::GLContextType fContextType;
+    GrGLStandard fForcedGpuApi;
     const int fSampleCount;
 };