Implement a benchmark for GrResourceCache

bench/InterpBench.cpp

 #include "SkBenchmark.h"
 #include "SkColorPriv.h"
 #include "SkMatrix.h"
 #include "SkRandom.h"
 #include "SkString.h"
 #include "SkPaint.h"
 
 #define TILE(x, width)  (((x) & 0xFFFF) * width >> 16)
 
 class InterpBench : public SkBenchmark {
     enum {
         kBuffer = 128,
         kLoop   = 20000
     };
     SkString    fName;
     int16_t     fDst[kBuffer];
     float       fFx, fDx;
 public:
     InterpBench(const char name[])  {
         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;
 
 protected:
     virtual int mulLoopCount() const { return 1; }
 
     virtual const char* onGetName() {
         return fName.c_str();
     }
@@ skipping 117 matching lines @@
     typedef InterpBench INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_BENCH( return new Fixed16D16Interp(); )
 DEF_BENCH( return new Fixed32D32Interp(); )
 DEF_BENCH( return new Fixed16D48Interp(); )
 DEF_BENCH( return new FloatInterp(); )
 DEF_BENCH( return new DoubleInterp(); )