Define iTunes location for media galleries tests.

chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm

 // 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.
 
 #include "chrome/browser/media_galleries/fileapi/itunes_finder_mac.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
+#import "base/mac/scoped_cftyperef.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/time/time.h"
+#include "chrome/browser/policy/preferences_mac.h"
 #include "content/public/browser/browser_thread.h"
 
 using base::mac::CFCast;
 using base::mac::CFToNSCast;
 
+namespace {
+
+static MacPreferences* g_mac_preferences = NULL;
+
+NSArray* GetItunesRecentDatabasePaths() {
+  scoped_ptr<MacPreferences> real_preferences;
+  MacPreferences* prefs = g_mac_preferences;
+  if (!prefs) {
+    real_preferences.reset(new MacPreferences());
+    prefs = real_preferences.get();
+  }
+  CFStringRef iapp_id = CFSTR("com.apple.iApps");
+  base::ScopedCFTypeRef<CFString> recent_database_path_key(
+      CFStringCreateWithCStringNoCopy(NULL, kITunesRecentDatabasePathsKey,
+                                      kCFStringEncodingASCII, NULL));
+  return CFToNSCast(CFCast<CFArrayRef>(prefs->CopyAppValue(
+      recent_database_path_key.get(), iapp_id)));
+}
+
+}  // namespace
+
 namespace itunes {
 
+const char kITunesRecentDatabasePathsKey[] = "iTunesRecentDatabasePaths";
+
 ITunesFinderMac::ITunesFinderMac(const ITunesFinderCallback& callback)
     : ITunesFinder(callback) {
 }
 
 ITunesFinderMac::~ITunesFinderMac() {}
 
+// static
+void ITunesFinderMac::SetMacPreferencesForTesting(MacPreferences* preferences) {
+  g_mac_preferences = preferences;
+}
+
 void ITunesFinderMac::FindITunesLibraryOnFileThread() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
 
-  CFStringRef iapp_id = CFSTR("com.apple.iApps");
-  CFStringRef itunes_db_key = CFSTR("iTunesRecentDatabasePaths");
-  base::scoped_nsobject<NSArray> plist(CFToNSCast(
-      CFCast<CFArrayRef>(CFPreferencesCopyAppValue(itunes_db_key, iapp_id))));
+  base::scoped_nsobject<NSArray> plist(GetItunesRecentDatabasePaths());
   if (!plist) {
     PostResultToUIThread(std::string());
     return;
   }
 
   // Find the most recently used iTunes XML database from the list of database
   // paths. Most of the time |plist| has a size of 1.
   base::Time most_recent_db_time;
   base::FilePath most_recent_db_path;
   for (NSString* path_ns in plist.get()) {
     NSString* expanded_path_ns = [path_ns stringByExpandingTildeInPath];
     base::FilePath db_path(base::mac::NSStringToFilePath(expanded_path_ns));
 
     base::PlatformFileInfo file_info;
     if (!file_util::GetFileInfo(db_path, &file_info))
       continue;
 
     // In case of two databases with the same modified time, tie breaker goes
     // to the first one on the list.
     if (file_info.last_modified <= most_recent_db_time)
       continue;
 
     most_recent_db_time = file_info.last_modified;
     most_recent_db_path = db_path;
   }
   PostResultToUIThread(most_recent_db_path.value());
 }
 
 }  // namespace itunes