Driver: use StringRef instead of raw pointer in lookupTypeForExtension() (NFC)

llvm-svn: 283611
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 863bd0a..9023265 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -370,7 +370,7 @@
   return GetProgramPath(DefaultLinker);
 }
 
-types::ID ToolChain::LookupTypeForExtension(const char *Ext) const {
+types::ID ToolChain::LookupTypeForExtension(StringRef Ext) const {
   return types::lookupTypeForExtension(Ext);
 }