Replace base::str[n]casecmp with helper functions.

extensions/browser/api/web_request/form_data_parser.cc

 // Copyright (c) 2012 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 "extensions/browser/api/web_request/form_data_parser.h"
 
 #include <vector>
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ skipping 297 matching lines @@
   enum ParserChoice {URL_ENCODED, MULTIPART, ERROR_CHOICE};
   ParserChoice choice = ERROR_CHOICE;
   std::string boundary;
 
   if (content_type_header == NULL) {
     choice = URL_ENCODED;
   } else {
     const std::string content_type(
         content_type_header->substr(0, content_type_header->find(';')));
 
-    if (base::strcasecmp(
-        content_type.c_str(), "application/x-www-form-urlencoded") == 0) {
+    if (base::EqualsCaseInsensitiveASCII(content_type,
+                                         "application/x-www-form-urlencoded")) {
       choice = URL_ENCODED;
-    } else if (base::strcasecmp(
-        content_type.c_str(), "multipart/form-data") == 0) {
+    } else if (base::EqualsCaseInsensitiveASCII(content_type,
+                                                "multipart/form-data")) {
       static const char kBoundaryString[] = "boundary=";
       size_t offset = content_type_header->find(kBoundaryString);
       if (offset == std::string::npos) {
         // Malformed header.
         return scoped_ptr<FormDataParser>();
       }
       offset += sizeof(kBoundaryString) - 1;
       boundary = content_type_header->substr(
           offset, content_type_header->find(';', offset));
       if (!boundary.empty())
@@ skipping 254 matching lines @@
   if (value_pattern().Match(header,
                             kContentDispositionLength, header.size(),
                             RE2::UNANCHORED, groups, 2)) {
     value->set(groups[1].data(), groups[1].size());
     *value_assigned = true;
   }
   return true;
 }
 
 }  // namespace extensions