Move MatchPattern to its own header and the base namespace.

base/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
@@ skipping 407 matching lines @@
     "sequenced_task_runner_helpers.h",
     "sha1.h",
     "sha1_portable.cc",
     "sha1_win.cc",
     "single_thread_task_runner.h",
     "stl_util.h",
     "strings/latin1_string_conversions.cc",
     "strings/latin1_string_conversions.h",
     "strings/nullable_string16.cc",
     "strings/nullable_string16.h",
+    "strings/pattern.cc",
+    "strings/pattern.h",
     "strings/safe_sprintf.cc",
     "strings/safe_sprintf.h",
     "strings/string16.cc",
     "strings/string16.h",
     "strings/string_number_conversions.cc",
     "strings/string_number_conversions.h",
     "strings/string_piece.cc",
     "strings/string_piece.h",
     "strings/string_split.cc",
     "strings/string_split.h",
@@ skipping 831 matching lines @@
     "profiler/tracked_time_unittest.cc",
     "rand_util_unittest.cc",
     "scoped_clear_errno_unittest.cc",
     "scoped_generic_unittest.cc",
     "scoped_native_library_unittest.cc",
     "security_unittest.cc",
     "sequence_checker_unittest.cc",
     "sha1_unittest.cc",
     "stl_util_unittest.cc",
     "strings/nullable_string16_unittest.cc",
+    "strings/pattern_unittest.cc",
     "strings/safe_sprintf_unittest.cc",
     "strings/string16_unittest.cc",
     "strings/string_number_conversions_unittest.cc",
     "strings/string_piece_unittest.cc",
     "strings/string_split_unittest.cc",
     "strings/string_tokenizer_unittest.cc",
     "strings/string_util_unittest.cc",
     "strings/stringize_macros_unittest.cc",
     "strings/stringprintf_unittest.cc",
     "strings/sys_string_conversions_mac_unittest.mm",
@@ skipping 273 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }