Implement a benchmark for GrResourceCache

bench/GrMemoryPoolBench.cpp

Index: bench/GrMemoryPoolBench.cpp
diff --git a/bench/GrMemoryPoolBench.cpp b/bench/GrMemoryPoolBench.cpp
index 0adf92abaa6f2f49ade2f7a6f5b056401a56c763..9eec19293e8cda7a8180e3bbdf2c556cc51edb19 100644
--- a/bench/GrMemoryPoolBench.cpp
+++ b/bench/GrMemoryPoolBench.cpp
@@ -33,8 +33,12 @@ GrMemoryPool A::gPool(10 * (1 << 10), 10 * (1 << 10));
 class GrMemoryPoolBenchStack : public SkBenchmark {
 public:
     GrMemoryPoolBenchStack()  {
-        fIsRendering = false;
     }
+
+    virtual bool isSuitableFor(Backend backend) SK_OVERRIDE {
+        return backend == kNonRendering_Backend;
+    }
+
 protected:
     virtual const char* onGetName() {
         return "grmemorypool_stack";
@@ -84,8 +88,12 @@ private:
 class GrMemoryPoolBenchRandom : public SkBenchmark {
 public:
     GrMemoryPoolBenchRandom()  {
-        fIsRendering = false;
     }
+
+    virtual bool isSuitableFor(Backend backend) SK_OVERRIDE {
+        return backend == kNonRendering_Backend;
+    }
+
 protected:
     virtual const char* onGetName() {
         return "grmemorypool_random";
@@ -121,8 +129,12 @@ class GrMemoryPoolBenchQueue : public SkBenchmark {
     };
 public:
     GrMemoryPoolBenchQueue()  {
-        fIsRendering = false;
     }
+
+    virtual bool isSuitableFor(Backend backend) SK_OVERRIDE {
+        return backend == kNonRendering_Backend;
+    }
+
 protected:
     virtual const char* onGetName() {
         return "grmemorypool_queue";