clang-format: Fix corner cases for comments in if conditions.

Before:
  if ( // a
          x + 3) { ..

After:
  if ( // a
      x + 3) { ..

llvm-svn: 208175
diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index f18984b..d225bce 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -290,10 +290,11 @@
     State.Stack.back().ContainsUnwrappedBuilder = true;
 
   State.Column += Spaces;
-  if (Current.is(tok::l_paren) && Previous.isOneOf(tok::kw_if, tok::kw_for))
+  if (Current.isNot(tok::comment) && Previous.is(tok::l_paren) &&
+      Previous.Previous && Previous.Previous->isOneOf(tok::kw_if, tok::kw_for))
     // Treat the condition inside an if as if it was a second function
     // parameter, i.e. let nested calls have a continuation indent.
-    State.Stack.back().LastSpace = State.Column + 1; // 1 is length of "(".
+    State.Stack.back().LastSpace = State.Column;
   else if (Current.isNot(tok::comment) &&
            (Previous.is(tok::comma) ||
             (Previous.is(tok::colon) && Previous.Type == TT_ObjCMethodExpr)))