Revert of Avoid calling strlen() where possible in base/trace_config

base/trace_event/trace_config.cc

Index: base/trace_event/trace_config.cc
diff --git a/base/trace_event/trace_config.cc b/base/trace_event/trace_config.cc
index 7ee9a4a101b4f13dcd4455be4a5406aa1b9e5e45..3df09992b12508b245a869f849f689cdcc4a5f3a 100644
--- a/base/trace_event/trace_config.cc
+++ b/base/trace_event/trace_config.cc
@@ -186,7 +186,7 @@
 }
 
 bool TraceConfig::EventFilterConfig::IsCategoryGroupEnabled(
-    const StringPiece& category_group_name) const {
+    const char* category_group_name) const {
   return category_filter_.IsCategoryGroupEnabled(category_group_name);
 }
 
@@ -277,7 +277,7 @@
 }
 
 bool TraceConfig::IsCategoryGroupEnabled(
-    const StringPiece& category_group_name) const {
+    const char* category_group_name) const {
   // TraceLog should call this method only as part of enabling/disabling
   // categories.
   return category_filter_.IsCategoryGroupEnabled(category_group_name);