Split TemplateHashMapImpl::Lookup into two methods

src/gdb-jit.cc

Index: src/gdb-jit.cc
diff --git a/src/gdb-jit.cc b/src/gdb-jit.cc
index 044f6fe3f423cf759da6ed69dcd10270610c7342..0664c6091a68f299db7822a69c06cf12eeb6c25f 100644
--- a/src/gdb-jit.cc
+++ b/src/gdb-jit.cc
@@ -1972,7 +1972,7 @@ static HashMap* GetLineMap() {
 
 static void PutLineInfo(Address addr, LineInfo* info) {
   HashMap* line_map = GetLineMap();
-  HashMap::Entry* e = line_map->Lookup(addr, HashCodeAddress(addr), true);
+  HashMap::Entry* e = line_map->LookupOrInsert(addr, HashCodeAddress(addr));
   if (e->value != NULL) delete static_cast<LineInfo*>(e->value);
   e->value = info;
 }