tools/gn: rename char_offset to column_number

tools/gn/c_include_iterator_unittest.cc

 // Copyright 2014 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 "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/c_include_iterator.h"
 #include "tools/gn/input_file.h"
 #include "tools/gn/location.h"
 
 namespace {
 
 bool RangeIs(const LocationRange& range,
              int line, int begin_char, int end_char) {
   return range.begin().line_number() == line &&
          range.end().line_number() == line &&
-         range.begin().char_offset() == begin_char &&
-         range.end().char_offset() == end_char;
+         range.begin().column_number() == begin_char &&
+         range.end().column_number() == end_char;
 }
 
 }  // namespace
 
 TEST(CIncludeIterator, Basic) {
   std::string buffer;
   buffer.append("// Some comment\n");
   buffer.append("\n");
   buffer.append("#include \"foo/bar.h\"\n");
   buffer.append("\n");
@@ skipping 120 matching lines @@
   InputFile file(SourceFile("//foo.cc"));
   file.SetContents(buffer);
 
   base::StringPiece contents;
   LocationRange range;
 
   CIncludeIterator iter(&file);
   EXPECT_TRUE(iter.GetNextIncludeString(&contents, &range));
   EXPECT_EQ("foo/bar.h", contents);
 }