Add GrSet class built on top of RedBlackTree

gyp/bench.gyp

 # GYP file to build performance testbench.
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
     {
       'target_name': 'bench',
       'type': 'executable',
@@ skipping 29 matching lines @@
         '../bench/DecodeBench.cpp',
         '../bench/DeferredCanvasBench.cpp',
         '../bench/DeferredSurfaceCopyBench.cpp',
         '../bench/DisplacementBench.cpp',
         '../bench/FSRectBench.cpp',
         '../bench/FontCacheBench.cpp',
         '../bench/FontScalerBench.cpp',
         '../bench/GameBench.cpp',
         '../bench/GrMemoryPoolBench.cpp',
         '../bench/GrResourceCacheBench.cpp',
+        '../bench/GrSetBench.cpp',
         '../bench/GradientBench.cpp',
         '../bench/HairlinePathBench.cpp',
         '../bench/ImageCacheBench.cpp',
         '../bench/ImageDecodeBench.cpp',
         '../bench/InterpBench.cpp',
         '../bench/LightingBench.cpp',
         '../bench/LineBench.cpp',
         '../bench/MagnifierBench.cpp',
         '../bench/MathBench.cpp',
         '../bench/Matrix44Bench.cpp',
@@ skipping 108 matching lines @@
         ['skia_gpu == 1', {
           'sources': [
             '../bench/BenchGpuTimer_gl.h',
             '../bench/BenchGpuTimer_gl.cpp',
           ],
         }],
       ],
     }
   ],
 }