Define iTunes location for media galleries tests.

chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm

Index: chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm
diff --git a/chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm b/chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm
index 3780160263982a9f35de8a998d938ec81cf53bc4..5a44902fd0936edaa83528116bbd4e673582fcca 100644
--- a/chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm
+++ b/chrome/browser/media_galleries/fileapi/itunes_finder_mac.mm
@@ -7,29 +7,56 @@
 #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;