Remove Sk prefix from some bench classes.

bench/SkGMBench.h

-/*
- * 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 "SkBenchmark.h"
-#include "gm.h"
-#include "SkCanvas.h"
-
-/**
- * Runs a GM as a benchmark by repeatedly drawing the GM.
- */
-class SkGMBench : public SkBenchmark {
-public:
-    // Constructor takes ownership of the GM param.
-    SkGMBench(skiagm::GM* gm);
-    virtual ~SkGMBench();
-
-protected:
-    virtual const char* onGetName() SK_OVERRIDE;
-    virtual bool isSuitableFor(Backend backend) SK_OVERRIDE;
-    virtual void onDraw(const int loops, SkCanvas* canvas) SK_OVERRIDE;
-    virtual SkIPoint onGetSize() SK_OVERRIDE;
-
-private:
-    skiagm::GM* fGM;
-    SkString    fName;
-    typedef SkBenchmark INHERITED;
-};