[clang-format] Add SpaceBeforeCpp11BracedList option.

WebKit C++ style for object initialization is as follows:

  Foo foo { bar };

Yet using clang-format -style=webkit changes this to:

  Foo foo{ bar };

As there is no existing combination of rules that will ensure a space
before a braced list in this fashion, this patch adds a new
SpaceBeforeCpp11BracedList rule.

Patch by Ross Kirsling!

Differential Revision: https://reviews.llvm.org/D46024

llvm-svn: 334692
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 7e62d15..71fc81a 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -449,6 +449,8 @@
                    Style.SpaceAfterTemplateKeyword);
     IO.mapOptional("SpaceBeforeAssignmentOperators",
                    Style.SpaceBeforeAssignmentOperators);
+    IO.mapOptional("SpaceBeforeCpp11BracedList",
+                   Style.SpaceBeforeCpp11BracedList);
     IO.mapOptional("SpaceBeforeCtorInitializerColon",
                    Style.SpaceBeforeCtorInitializerColon);
     IO.mapOptional("SpaceBeforeInheritanceColon",
@@ -697,6 +699,7 @@
   LLVMStyle.SpaceBeforeParens = FormatStyle::SBPO_ControlStatements;
   LLVMStyle.SpaceBeforeRangeBasedForLoopColon = true;
   LLVMStyle.SpaceBeforeAssignmentOperators = true;
+  LLVMStyle.SpaceBeforeCpp11BracedList = false;
   LLVMStyle.SpacesInAngles = false;
 
   LLVMStyle.PenaltyBreakAssignment = prec::Assignment;
@@ -892,6 +895,7 @@
   Style.ObjCBlockIndentWidth = 4;
   Style.ObjCSpaceAfterProperty = true;
   Style.PointerAlignment = FormatStyle::PAS_Left;
+  Style.SpaceBeforeCpp11BracedList = true;
   return Style;
 }
 
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index ea95769..3280f25 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2548,6 +2548,9 @@
   if (Style.isCpp()) {
     if (Left.is(tok::kw_operator))
       return Right.is(tok::coloncolon);
+    if (Right.is(tok::l_brace) && Right.BlockKind == BK_BracedInit &&
+        !Left.opensScope() && Style.SpaceBeforeCpp11BracedList)
+      return true;
   } else if (Style.Language == FormatStyle::LK_Proto ||
              Style.Language == FormatStyle::LK_TextProto) {
     if (Right.is(tok::period) &&