rename tracing parameter to be more consistent with other methods

src/utils/SkEventTracer.cpp

Index: src/utils/SkEventTracer.cpp
diff --git a/src/utils/SkEventTracer.cpp b/src/utils/SkEventTracer.cpp
index 4b37e95be4cbc2d2dc8d25a5dfa8a9439828c374..fff13741d42955878b25775457460924fcff0102 100644
--- a/src/utils/SkEventTracer.cpp
+++ b/src/utils/SkEventTracer.cpp
@@ -30,7 +30,7 @@ class SkDefaultEventTracer: public SkEventTracer {
         return &no;
     };
     virtual const char* getCategoryGroupName(
-      const uint8_t* category_group_enabled) SK_OVERRIDE {
+      const uint8_t* categoryEnabledFlag) SK_OVERRIDE {
         static const char* dummy = "dummy";
         return dummy;
     };