gpu: Rename Capabilities::map_image to Capabilities::image.

cc/resources/raster_worker_pool_perftest.cc

Index: cc/resources/raster_worker_pool_perftest.cc
diff --git a/cc/resources/raster_worker_pool_perftest.cc b/cc/resources/raster_worker_pool_perftest.cc
index 658435658f1d72407fc97b5d3aabc8f6a21b735f..3ae1c20f6e91736c7eab56bb53e97c3bfaf1210d 100644
--- a/cc/resources/raster_worker_pool_perftest.cc
+++ b/cc/resources/raster_worker_pool_perftest.cc
@@ -69,7 +69,7 @@ class PerfContextProvider : public ContextProvider {
   virtual bool BindToCurrentThread() OVERRIDE { return true; }
   virtual Capabilities ContextCapabilities() OVERRIDE {
     Capabilities capabilities;
-    capabilities.gpu.map_image = true;
+    capabilities.gpu.image = true;
     capabilities.gpu.sync_query = true;
     return capabilities;
   }