Don't break line comments with escaped newlines.

Summary:
These can appear when comments contain command lines with quoted line
breaks. As the text (including escaped newlines and '//' from consecutive lines)
is a single line comment, we used to break it even when it didn't exceed column
limit. This is a temporary solution, in the future we may want to support this
case completely - at least adjust leading whitespace when changing indentation
of the first line.

Reviewers: djasper

Reviewed By: djasper

CC: cfe-commits, klimek

Differential Revision: http://llvm-reviews.chandlerc.com/D1146

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186456 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index 6f6f468..67a0fa8 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -967,8 +967,9 @@
                Current->is(tok::string_literal) &&
                Current->Previous->isNot(tok::lessless) &&
                Current->Previous->Type != TT_InlineASMColon &&
-               Current->getNextNonComment() &&
-               Current->getNextNonComment()->is(tok::string_literal)) {
+               ((Current->getNextNonComment() &&
+                 Current->getNextNonComment()->is(tok::string_literal)) ||
+                (Current->TokenText.find("\\\n") != StringRef::npos))) {
       Current->MustBreakBefore = true;
     }
     Current->CanBreakBefore =