[SyncFS] [Refactoring] Change RemovePrefix() to return bool

chrome/browser/sync_file_system/drive_backend/metadata_database_index.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 "chrome/browser/sync_file_system/drive_backend/metadata_database_index.h"
 
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/sync_file_system/drive_backend/drive_backend_constants.h"
@@ skipping 67 matching lines @@
 void ReadDatabaseContents(leveldb::DB* db,
                           DatabaseContents* contents) {
   DCHECK(db);
   DCHECK(contents);
 
   scoped_ptr<leveldb::Iterator> itr(db->NewIterator(leveldb::ReadOptions()));
   for (itr->SeekToFirst(); itr->Valid(); itr->Next()) {
     std::string key = itr->key().ToString();
     std::string value = itr->value().ToString();
 
-    if (StartsWithASCII(key, kFileMetadataKeyPrefix, true)) {
-      std::string file_id = RemovePrefix(key, kFileMetadataKeyPrefix);
-
+    std::string file_id;
+    if (RemovePrefix(key, kFileMetadataKeyPrefix, &file_id)) {
       scoped_ptr<FileMetadata> metadata(new FileMetadata);
       if (!metadata->ParseFromString(itr->value().ToString())) {
         util::Log(logging::LOG_WARNING, FROM_HERE,
                   "Failed to parse a FileMetadata");
         continue;
       }
 
       contents->file_metadata.push_back(metadata.release());
       continue;
     }
 
-    if (StartsWithASCII(key, kFileTrackerKeyPrefix, true)) {
+    std::string tracker_id_str;
+    if (RemovePrefix(key, kFileTrackerKeyPrefix, &tracker_id_str)) {
       int64 tracker_id = 0;
-      if (!base::StringToInt64(RemovePrefix(key, kFileTrackerKeyPrefix),
-                               &tracker_id)) {
+      if (!base::StringToInt64(tracker_id_str, &tracker_id)) {
         util::Log(logging::LOG_WARNING, FROM_HERE,
                   "Failed to parse TrackerID");
         continue;
       }
 
       scoped_ptr<FileTracker> tracker(new FileTracker);
       if (!tracker->ParseFromString(itr->value().ToString())) {
         util::Log(logging::LOG_WARNING, FROM_HERE,
                   "Failed to parse a Tracker");
         continue;
@@ skipping 574 matching lines @@
 
     DVLOG(3) << "  Remove from dirty_trackers_: " << tracker_id;
     dirty_trackers_.erase(tracker_id);
 
     demoted_dirty_trackers_.erase(tracker_id);
   }
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system