Have gpu createTestingOlyBackendTexture know if it is a render target or not

src/gpu/gl/GrGLGpu.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLGpu_DEFINED
 #define GrGLGpu_DEFINED
 
@@ skipping 115 matching lines @@
 
     void invalidateBoundRenderTarget() {
         fHWBoundRenderTargetUniqueID = SK_InvalidUniqueID;
     }
 
     GrStencilAttachment* createStencilAttachmentForRenderTarget(const GrRenderTarget* rt,
                                                                 int width,
                                                                 int height) override;
 
     GrBackendObject createTestingOnlyBackendTexture(void* pixels, int w, int h,
-                                                    GrPixelConfig config) override;
+                                                    GrPixelConfig config,
+                                                    bool isRenderTarget = false) override;
     bool isTestingOnlyBackendTexture(GrBackendObject) const override;
     void deleteTestingOnlyBackendTexture(GrBackendObject, bool abandonTexture) override;
 
     void resetShaderCacheForTesting() const override;
 
     void drawDebugWireRect(GrRenderTarget*, const SkIRect&, GrColor) override;
 
     void finishDrawTarget() override;
 
 private:
@@ skipping 447 matching lines @@
     bool fHWPLSEnabled;
     bool fPLSHasBeenUsed;
 
     float fHWMinSampleShading;
 
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.
 };
 
 #endif