Remove Sk prefix from some bench classes.

bench/MatrixBench.cpp

Index: bench/MatrixBench.cpp
diff --git a/bench/MatrixBench.cpp b/bench/MatrixBench.cpp
index fa19fc8157aa59aa01b55bf251c1cf85bca26da8..78482d963d49f8858d64940cd170758a502e69e0 100644
--- a/bench/MatrixBench.cpp
+++ b/bench/MatrixBench.cpp
@@ -5,13 +5,13 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-#include "SkBenchmark.h"
+#include "Benchmark.h"
 #include "SkMatrix.h"
 #include "SkMatrixUtils.h"
 #include "SkRandom.h"
 #include "SkString.h"
 
-class MatrixBench : public SkBenchmark {
+class MatrixBench : public Benchmark {
     SkString    fName;
 public:
     MatrixBench(const char name[])  {
@@ -38,7 +38,7 @@ protected:
     }
 
 private:
-    typedef SkBenchmark INHERITED;
+    typedef Benchmark INHERITED;
 };