clang_getCXTUResourceUsage: report memory used by HeaderSearch.

This required converting the StringMaps to use a BumpPtrAllocator.  I measured the
compile time and saw no observable regression.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136190 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 6b073f5..829649a 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -5458,6 +5458,9 @@
     case CXTUResourceUsage_SourceManager_DataStructures:
       str = "SourceManager: data structures and tables";
       break;
+    case CXTUResourceUsage_Preprocessor_HeaderSearch:
+      str = "Preprocessor: header search tables";
+      break;
   }
   return str;
 }
@@ -5543,6 +5546,9 @@
                                  pRec->getTotalMemory());    
   }
   
+  createCXTUResourceUsageEntry(*entries,
+                               CXTUResourceUsage_Preprocessor_HeaderSearch,
+                               pp.getHeaderSearchInfo().getTotalMemory());
   
   CXTUResourceUsage usage = { (void*) entries.get(),
                             (unsigned) entries->size(),