Small cleanup: Don't duplicate default behavior.

std::unique_ptr is null initialized and reset default to null.

Thanks to David Blaikie for noticing.

llvm-svn: 215560

clang/lib/Frontend/ASTUnit.cpp

@@ -219,7 +219,7 @@ ASTUnit::ASTUnit(bool _MainFileIsAST)
     TUKind(TU_Complete), WantTiming(getenv("LIBCLANG_TIMING")),
     OwnsRemappedFileBuffers(true),
     NumStoredDiagnosticsFromDriver(0),
-    PreambleRebuildCounter(0), SavedMainFileBuffer(nullptr),
+    PreambleRebuildCounter(0),
     NumWarningsInPreamble(0),
     ShouldCacheCodeCompletionResults(false),
     IncludeBriefCommentsInCodeCompletion(false), UserFilesAreVolatile(false),
@@ -1026,7 +1026,7 @@ static void checkAndSanitizeDiags(SmallVectorImpl<StoredDiagnostic> &
 /// \returns True if a failure occurred that causes the ASTUnit not to
 /// contain any translation-unit information, false otherwise.
 bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
-  SavedMainFileBuffer.reset(nullptr);
+  SavedMainFileBuffer.reset();
 
   if (!Invocation) {
     delete OverrideMainBuffer;