PPCallbacks: Add hook for reaching the end of the main file, and fix DependencyFile to not do work in its destructor.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@99257 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 9d59300..8b4b1dd 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -519,6 +519,11 @@
   return EnterSourceFile(FID, 0, ErrorStr);
 }
 
+void Preprocessor::EndSourceFile() {
+  // Notify the client that we reached the end of the source file.
+  if (Callbacks)
+    Callbacks->EndOfMainFile();
+}
 
 //===----------------------------------------------------------------------===//
 // Lexer Event Handling.