NOCOMMIT: Blink tracing now uses base

base/trace_event/trace_event.h

Index: base/trace_event/trace_event.h
diff --git a/base/trace_event/trace_event.h b/base/trace_event/trace_event.h
index c3b20fc58d0584bca3c578ff21e3c8868b8b53bb..bf304de2ede16daade238b70c78a596773920951 100644
--- a/base/trace_event/trace_event.h
+++ b/base/trace_event/trace_event.h
@@ -45,6 +45,13 @@
         trace_event_internal::                     \
         TraceEventSamplingStateScope<bucket_number>::Set(category "\0" name)
 
+// Sets a current sampling state of the given bucket.
+// |categoryAndName| doesn't need to be a constant string.
+// The format of the string is "category\0name".
+#define TRACE_EVENT_SET_NONCONST_SAMPLING_STATE_FOR_BUCKET(bucket_number, category_and_name) \
+    trace_event_internal::                     \
+    TraceEventSamplingStateScope<bucket_number>::Set(category_and_name)
+
 // Returns a current sampling state of the given bucket.
 #define TRACE_EVENT_GET_SAMPLING_STATE_FOR_BUCKET(bucket_number) \
     trace_event_internal::TraceEventSamplingStateScope<bucket_number>::Current()