[PATCH] Speed up clang-tidy when profiling in on.

[Alexander Kornienko]

Looks good!

================
Comment at: lib/ASTMatchers/ASTMatchFinder.cpp:494
@@ -491,3 +493,3 @@
 private:
-  class TimeRegion {
+  class TimeBucketRegion {
   public:
----------------
Please add a short comment on how to use this class.

http://reviews.llvm.org/D5972