Revert of Return GrGLContext from GrTestTarget

tests/ResourceCacheTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 // Include here to ensure SK_SUPPORT_GPU is set correctly before it is examined.
 #include "SkTypes.h"
 
@@ skipping 163 matching lines @@
                         smallMSAART0->asRenderTarget()->renderTargetPriv().getStencilAttachment() !=
                         smallMSAART1->asRenderTarget()->renderTargetPriv().getStencilAttachment());
         }
     }
 }
 
 static void test_wrapped_resources(skiatest::Reporter* reporter, GrContext* context) {
     GrTestTarget tt;
     context->getTestTarget(&tt);
 
-    const GrGLInterface* gl = tt.glContext()->interface();
+    const GrGLInterface* gl = tt.glInterface();
     if (!gl) {
         return;
     }
 
     GrGLuint texIDs[2];
     static const int kW = 100;
     static const int kH = 100;
     GR_GL_CALL(gl, GenTextures(2, texIDs));
     GR_GL_CALL(gl, ActiveTexture(GR_GL_TEXTURE0));
     GR_GL_CALL(gl, PixelStorei(GR_GL_UNPACK_ALIGNMENT, 1));
@@ skipping 1075 matching lines @@
     test_scratch_key_consistency(reporter);
     test_purge_invalidated(reporter);
     test_cache_chained_purge(reporter);
     test_resource_size_changed(reporter);
     test_timestamp_wrap(reporter);
     test_flush(reporter);
     test_large_resource_count(reporter);
 }
 
 #endif