Label non-capturing groups if no capturing needed

components/autofill/core/browser/form_field_unittest.cc

 // Copyright 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 "components/autofill/core/browser/form_field.h"
 
 #include <string>
 
 #include "base/memory/scoped_vector.h"
 #include "base/strings/string16.h"
@@ skipping 70 matching lines @@
   field.label = ASCIIToUTF16("head_tail");
   EXPECT_TRUE(FormField::Match(&field, "head|other", FormField::MATCH_LABEL));
   EXPECT_TRUE(FormField::Match(&field, "tail|other", FormField::MATCH_LABEL));
   EXPECT_FALSE(FormField::Match(&field, "bad|good", FormField::MATCH_LABEL));
 
   // Case sensitivity.
   field.label = ASCIIToUTF16("xxxHeAd_tAiLxxx");
   EXPECT_TRUE(FormField::Match(&field, "head_tail", FormField::MATCH_LABEL));
 
   // Word boundaries.
-  const std::string kWordBoundary = "(\\A|\\z|\\PL)";
+  const std::string kWordBoundary = "(?:\\A|\\z|\\PL)";
   field.label = ASCIIToUTF16("contains word:");
   EXPECT_TRUE(FormField::Match(&field, kWordBoundary + "word" + kWordBoundary,
                                FormField::MATCH_LABEL));
   EXPECT_FALSE(FormField::Match(&field, kWordBoundary + "con" + kWordBoundary,
                                 FormField::MATCH_LABEL));
   // Make sure the circumflex in 'crepe' is not treated as a word boundary.
   field.label = base::UTF8ToUTF16("cr" "\xC3\xAA" "pe");
   EXPECT_FALSE(FormField::Match(&field, kWordBoundary + "cr" + kWordBoundary,
                                 FormField::MATCH_LABEL));
 }
@@ skipping 30 matching lines @@
   FormField::ParseFormFields(fields.get(), true, &field_type_map);
   ASSERT_EQ(3U, field_type_map.size());
 
   EXPECT_EQ(ADDRESS_HOME_LINE1,
             field_type_map.find(ASCIIToUTF16("Address line1"))->second);
   EXPECT_EQ(ADDRESS_HOME_LINE2,
             field_type_map.find(ASCIIToUTF16("Address line2"))->second);
 }
 
 }  // namespace autofill