Enable compiling GN by default.

tools/gn/string_utils.cc

 // Copyright (c) 2013 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.
 
 #include "tools/gn/string_utils.h"
 
 #include "tools/gn/err.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/token.h"
 #include "tools/gn/tokenizer.h"
 #include "tools/gn/value.h"
 
 namespace {
 
 // Constructs an Err indicating a range inside a string. We assume that the
 // token has quotes around it that are not counted by the offset.
 Err ErrInsideStringToken(const Token& token, size_t offset, size_t size,
                          const std::string& msg,
                          const std::string& help = std::string()) {
   // The "+1" is skipping over the " at the beginning of the token.
+  int int_offset = static_cast<int>(offset);
   Location begin_loc(token.location().file(),
                      token.location().line_number(),
-                     token.location().char_offset() + offset + 1);
+                     token.location().char_offset() + int_offset + 1);
   Location end_loc(token.location().file(),
                    token.location().line_number(),
-                   token.location().char_offset() + offset + 1 + size);
+                   token.location().char_offset() + int_offset + 1 +
+                   static_cast<int>(size));
   return Err(LocationRange(begin_loc, end_loc), msg, help);
 }
 
 // Given the character input[i] indicating the $ in a string, locates the
 // identifier and places its range in |*identifier|, and updates |*i| to
 // point to the last character consumed.
 //
 // On error returns false and sets the error.
 bool LocateInlineIdenfitier(const Token& token,
                             const char* input, size_t size,
@@ skipping 122 matching lines @@
     }
   }
   return true;
 }
 
 std::string RemovePrefix(const std::string& str, const std::string& prefix) {
   CHECK(str.size() >= prefix.size() &&
         str.compare(0, prefix.size(), prefix) == 0);
   return str.substr(prefix.size());
 }