Make blink::protocol::StringBuilder a distinct type from WTF::StringBuilder.

components/ui_devtools/string_util.h

 // Copyright 2016 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.
 
 #ifndef COMPONENTS_UI_DEVTOOLS_STRING_UTIL_H_
 #define COMPONENTS_UI_DEVTOOLS_STRING_UTIL_H_
 
 #include <memory>
 
 #include "base/json/json_reader.h"
@@ skipping 27 matching lines @@
 
 class StringUtil {
  public:
   static String substring(const String& s, unsigned pos, unsigned len) {
     return s.substr(pos, len);
   }
   static String fromInteger(int number) { return base::IntToString(number); }
   static String fromDouble(double number) {
     return base::DoubleToString(number);
   }
+  static void builderAppend(StringBuilder& builder, const String& s) {
+    builder.append(s);
+  }
+  static void builderAppend(StringBuilder& builder, char c) {
+    builder.append(c);
+  }
+  static void builderAppend(StringBuilder& builder, const char* s, size_t len) {
+    builder.append(s, len);
+  }
   static void builderReserve(StringBuilder& builder, unsigned capacity) {
     builder.reserveCapacity(capacity);
   }
+  static String builderToString(StringBuilder& builder) {
+    return builder.toString();
+  }
   static const size_t kNotFound = static_cast<size_t>(-1);
   static std::unique_ptr<Value> parseJSON(const String& string);
 };
 
 }  // namespace protocol
 }  // namespace devtools
 }  // namespace ui
 
 #endif  // COMPONENTS_UI_DEVTOOLS_STRING_UTIL_H_