Index: lib/Format/Format.cpp
===================================================================
--- lib/Format/Format.cpp
+++ lib/Format/Format.cpp
@@ -675,6 +675,11 @@
   if (Language == FormatStyle::LK_TextProto) {
     FormatStyle GoogleStyle = getGoogleStyle(FormatStyle::LK_Proto);
     GoogleStyle.Language = FormatStyle::LK_TextProto;
+
+    // In protos, string literals are commonly multiline and already broken-up.
+    // Don't break them up even further, especially since we don't support
+    // reflowing them.
+    GoogleStyle.BreakStringLiterals = false;
     return GoogleStyle;
   }