Fix Mac window frame coordinate conversion on multiple monitor setups

chrome/browser/automation/automation_provider_mac.mm

 // Copyright (c) 2009 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/automation/automation_provider.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "app/l10n_util.h"
 #include "app/l10n_util_mac.h"
 #include "base/gfx/point.h"
 #include "base/gfx/rect.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/cocoa/tab_window_controller.h"
 #include "chrome/test/automation/automation_messages.h"
 #include "grit/generated_resources.h"
 
 void AutomationProvider::SetWindowBounds(int handle, const gfx::Rect& bounds,
                                          bool* success) {
   *success = false;
   NSWindow* window = window_tracker_->GetResource(handle);
   if (window) {
     NSRect new_bounds = NSRectFromCGRect(bounds.ToCGRect());
 
-    // This is likely incorrect for a multiple-monitor setup; OK because this
-    // is used only for testing purposes.
-    new_bounds.origin.y = [[window screen] frame].size.height -
-        new_bounds.origin.y - new_bounds.size.height;
+    if ([[NSScreen screens] count] > 0) {
+      new_bounds.origin.y =
+          [[[NSScreen screens] objectAtIndex:0] frame].size.height -
+          new_bounds.origin.y - new_bounds.size.height;
+    }
 
     [window setFrame:new_bounds display:NO];
     *success = true;
   }
 }
 
 void AutomationProvider::SetWindowVisible(int handle, bool visible,
                                           bool* result) {
   *result = false;
   NSWindow* window = window_tracker_->GetResource(handle);
@@ skipping 112 matching lines @@
   // If we don't yet have a title, use "Untitled".
   if (![title length]) {
     text->assign(WideToUTF16(l10n_util::GetString(
         IDS_BROWSER_WINDOW_MAC_TAB_UNTITLED)));
     return;
   }
 
   text->assign(base::SysNSStringToUTF16(title));
 }