Implement a benchmark for GrResourceCache

bench/MutexBench.cpp

Index: bench/MutexBench.cpp
diff --git a/bench/MutexBench.cpp b/bench/MutexBench.cpp
index 1d037ec1cd27da247e63c012c641361315918dc5..0fd6775c77c4f725db490ffa91395961d5b0a7e3 100644
--- a/bench/MutexBench.cpp
+++ b/bench/MutexBench.cpp
@@ -10,8 +10,12 @@
 class MutexBench : public SkBenchmark {
 public:
     MutexBench()  {
-        fIsRendering = false;
     }
+
+    virtual bool isSuitableFor(Backend backend) SK_OVERRIDE {
+        return backend == kNonRendering_Backend;
+    }
+
 protected:
     virtual const char* onGetName() {
         return "mutex";