Rework HeaderSearch's interface for getting a module from a name and
for getting the name of the module file, unifying the code for
searching for a module with a given name (into lookupModule()) and
separating out the mapping to a module file (into
getModuleFileName()). No functionality change.

llvm-svn: 149197
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index e99e47e..669fe4a 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -226,7 +226,8 @@
   }
   
   // Dig out the module definition.
-  Module = HS.getModule(CI.getLangOpts().CurrentModule, /*AllowSearch=*/false);
+  Module = HS.lookupModule(CI.getLangOpts().CurrentModule, 
+                           /*AllowSearch=*/false);
   if (!Module) {
     CI.getDiagnostics().Report(diag::err_missing_module)
       << CI.getLangOpts().CurrentModule << Filename;