Revert to Immersive Fullscreen on OSX for a special case

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright 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 "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 #include <utility>
 
@@ skipping 82 matching lines @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #import "ui/base/cocoa/cocoa_base_utils.h"
 #import "ui/base/cocoa/nsview_additions.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #include "ui/gfx/mac/scoped_cocoa_disable_screen_updates.h"
+#include "ui/gfx/screen.h"
 
 using bookmarks::BookmarkModel;
 using bookmarks::BookmarkNode;
 using l10n_util::GetStringUTF16;
 using l10n_util::GetNSStringWithFixup;
 using l10n_util::GetNSStringFWithFixup;
 
 // ORGANIZATION: This is a big file. It is (in principle) organized as follows
 // (in order):
 // 1. Interfaces. Very short, one-time-use classes may include an implementation
@@ skipping 1906 matching lines @@
   } else {
     [self enterImmersiveFullscreen];
     DCHECK(!url.is_empty());
     [self updateFullscreenExitBubbleURL:url bubbleType:bubbleType];
   }
 }
 
 - (void)enterWebContentFullscreenForURL:(const GURL&)url
                              bubbleType:(ExclusiveAccessBubbleType)bubbleType {
   // HTML5 Fullscreen should only use AppKit fullscreen in 10.10+.
+  // However, if the user is using multiple monitors and turned off
+  // "Separate Space in Each Display", use Immersive Fullscreen so
+  // that the other monitors won't blank out.
+  gfx::Screen* screen = gfx::Screen::GetScreen();
+  BOOL hasMultipleMonitors = screen && screen->GetNumDisplays() > 1;
   if (chrome::mac::SupportsSystemFullscreen() &&
-      base::mac::IsOSYosemiteOrLater())
+      base::mac::IsOSYosemiteOrLater() &&
+      !(hasMultipleMonitors && ![NSScreen screensHaveSeparateSpaces])) {
     [self enterAppKitFullscreen];
-  else
+  } else {
     [self enterImmersiveFullscreen];
+  }
 
   if (!url.is_empty())
     [self updateFullscreenExitBubbleURL:url bubbleType:bubbleType];
 }
 
 - (void)exitAnyFullscreen {
   // TODO(erikchen): Fullscreen modes should stack. Should be able to exit
   // Immersive Fullscreen and still be in AppKit Fullscreen.
   if ([self isInAppKitFullscreen])
     [self exitAppKitFullscreen];
@@ skipping 86 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)