Fix iossim's support for retina devices.

testing/iossim/iossim.mm

 // 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.
 
 #import <Foundation/Foundation.h>
 #include <asl.h>
 #include <libgen.h>
 #include <stdarg.h>
 #include <stdio.h>
 
@@ skipping 473 matching lines @@
 // Creates the necessary directory structure under the given user home directory
 // path, then sets the path in the appropriate environment variable.
 // Returns YES if successful, NO if unable to create or initialize the given
 // directory.
 BOOL InitializeSimulatorUserHome(NSString* userHomePath, NSString* deviceName) {
   if (!CreateHomeDirSubDirs(userHomePath))
     return NO;
 
   // Set the device to simulate. Note that the iOS Simulator must not be running
   // for this setting to take effect.
-  NSMutableDictionary* plistDict =
-      [NSMutableDictionary dictionaryWithObject:deviceName
-                                         forKey:@"SimulateDevice"];
-  NSString* plistPath = @"Library/Preferences/com.apple.iphonesimulator.plist";
-  [plistDict writeToFile:[userHomePath stringByAppendingPathComponent:plistPath]
-              atomically:YES];
+  CFStringRef iPhoneSimulatorAppID = CFSTR("com.apple.iphonesimulator");
+  CFPreferencesSetAppValue(CFSTR("SimulateDevice"),
+                           deviceName,
+                           iPhoneSimulatorAppID);
+  CFPreferencesAppSynchronize(iPhoneSimulatorAppID);
 
   // Update the environment to use the specified directory as the user home
   // directory.
   // Note: the third param of setenv specifies whether or not to overwrite the
   // variable's value if it has already been set.
   if ((setenv(kUserHomeEnvVariable, [userHomePath UTF8String], YES) == -1) ||
       (setenv(kHomeEnvVariable, [userHomePath UTF8String], YES) == -1)) {
     LogError(@"Unable to set environment variables for home directory.");
     return NO;
   }
@@ skipping 209 matching lines @@
              [error localizedDescription],
              [error domain], static_cast<long int>([error code]));
   }
 
   // Note that this code is only executed if the simulator fails to start
   // because once the main run loop is started, only the delegate calling
   // exit() will end the program.
   [pool drain];
   return kExitFailure;
 }