Implement a benchmark for GrResourceCache

bench/InterpBench.cpp

Index: bench/InterpBench.cpp
diff --git a/bench/InterpBench.cpp b/bench/InterpBench.cpp
index f43c37e77d51d390955bccb1e3bb18e7abf74da3..9cd99df0171dbcd316e03ef88381df7d296cfe53 100644
--- a/bench/InterpBench.cpp
+++ b/bench/InterpBench.cpp
@@ -20,7 +20,10 @@ public:
         fName.printf("interp_%s", name);
         fFx = 3.3f;
         fDx = 0.1257f;
-        fIsRendering = false;
+    }
+
+    virtual bool isSuitableFor(Backend backend) SK_OVERRIDE {
+        return backend == kNonRendering_Backend;
     }
 
     virtual void performTest(int16_t dst[], float x, float dx, int count) = 0;