Remove Sk prefix from some bench classes.

bench/ColorPrivBench.cpp

Index: bench/ColorPrivBench.cpp
diff --git a/bench/ColorPrivBench.cpp b/bench/ColorPrivBench.cpp
index 9c15a8400c0dcaf5be53f999446e1162911ead01..01810ed2399dfc47191750a5c1c8ce92d92e8cae 100644
--- a/bench/ColorPrivBench.cpp
+++ b/bench/ColorPrivBench.cpp
@@ -1,10 +1,10 @@
-#include "SkBenchmark.h"
+#include "Benchmark.h"
 #include "SkColorPriv.h"
 #include "SkRandom.h"
 #include "SkString.h"
 
 template <bool kFast, bool kScale>
-class FourByteInterpBench : public SkBenchmark {
+class FourByteInterpBench : public Benchmark {
 public:
     FourByteInterpBench() {
         fName.set("four_byte_interp");