Capitalize WTF-based type traits as lower_case

tools/clang/rewrite_to_chrome_style/tests/fields-expected.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 namespace blink {
 
 // Note: do not add any copy or move constructors to this class: doing so will
 // break test coverage that we don't clobber the class name by trying to emit
 // replacements for synthesized functions.
 class C {
@@ skipping 50 matching lines @@
 union U {
   char four_chars[4];
   short two_shorts[2];
   int one_hopefully_four_byte_int;
   int has_prefix_;
 };
 
 // https://crbug.com/640749#c1: Some type traits are inside blink namespace.
 struct IsGarbageCollectedMixin {
   static const bool value = true;
+  static const bool safe_to_compare_to_empty_or_deleted = false;
 };
 
 }  // namespace blink
 
+namespace not_blink {
+
+// These are traits for WTF types that may be defined outside of blink such
+// as in mojo. But their names are unique so we can globally treat them as
+// type traits for renaming.
+struct GloballyKnownTraits {
+  static const bool safe_to_compare_to_empty_or_deleted = false;
+};
+
+}  // namespace not_blink
+
 namespace WTF {
 
 // We don't want to capitalize fields in type traits
 // (i.e. the |value| -> |kValue| rename is undesirable below).
 struct TypeTrait1 {
   static const bool value = true;
 };
 
 // Some type traits are implemented as classes, not structs
 // (e.g. WTF::IsGarbageCollectedType or WTF::IsAssignable).
@@ skipping 81 matching lines @@
   // Test that references to a static field are correctly rewritten.
   blink::C::instance_count_++;
   // Force instantiation of a copy constructor for blink::C to make sure field
   // initializers for synthesized functions don't cause weird rewrites.
   blink::C c;
   blink::C c2 = c;
 
   bool b1 = WTF::TypeTrait1::value;
   bool b2 = WTF::TypeTrait2<void>::value;
 }