[clang-format] Add style option AllowShortLambdasOnASingleLine

Summary:
This option `AllowShortLambdasOnASingleLine` similar to the other `AllowShort*` options, but applied to C++ lambdas.

Reviewers: djasper, klimek

Reviewed By: klimek

Subscribers: MyDeveloperDay, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D57687

llvm-svn: 357027
diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 5c7ab12..010b086 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -1475,6 +1475,7 @@
       return true;
     }
   }
+  FormatTok->Type = TT_LambdaLBrace;
   LSquare.Type = TT_LambdaLSquare;
   parseChildBlock();
   return true;