[frontend] Make -chain-include work when used with modules.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180633 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 6031ad2..ece51a3 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -294,6 +294,8 @@
       source.reset(ChainedIncludesSource::create(CI));
       if (!source)
         goto failure;
+      CI.setModuleManager(static_cast<ASTReader*>(
+         &static_cast<ChainedIncludesSource*>(source.get())->getFinalReader()));
       CI.getASTContext().setExternalSource(source);
 
     } else if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {