Revert of Return GrGLContext from GrTestTarget

src/gpu/gl/GrGLGpu.h

Index: src/gpu/gl/GrGLGpu.h
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index 4872db7309d656ccea5bb92b5767a99be2469681..98d0ffcd33fda92912980e33ec0f7221b9ae6df5 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -109,8 +109,8 @@
                           const GrPipeline&,
                           const GrBatchTracker&) const override;
 
-    const GrGLContext* glContextForTesting() const override {
-        return &this->glContext();
+    virtual const GrGLInterface* glInterfaceForTesting() const {
+        return this->glInterface();
     }
 
 private:
@@ -300,7 +300,7 @@
 
     void unbindTextureFromFBO(GrGLenum fboTarget);
 
-    SkAutoTUnref<GrGLContext>  fGLContext;
+    SkAutoTDelete<GrGLContext>  fGLContext;
 
     void createCopyProgram();