Hide the fullscreen toolbar only for FramedBrowserWindow

chrome/browser/ui/cocoa/browser_window_controller_private.mm

Index: chrome/browser/ui/cocoa/browser_window_controller_private.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_controller_private.mm b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
index 0fdcfa38db91b676b04156afd53bda05c5d67a61..15d185de320c80b80bc3dd0f54a42013ff6ae0aa 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -100,6 +100,14 @@ void RecordFullscreenStyle(FullscreenStyle style) {
 
 }  // namespace
 
+@interface NSWindow (NSPrivateApis)
+// Note: These functions are private, use -[NSObject respondsToSelector:]
+// before calling them.
+
+- (NSWindow*)_windowForToolbar;
+
+@end
+
 @implementation BrowserWindowController(Private)
 
 // Create the tab strip controller.
@@ -712,6 +720,15 @@ willPositionSheet:(NSWindow*)sheet
     for (NSWindow* window in [[NSApplication sharedApplication] windows]) {
       if ([window
               isKindOfClass:NSClassFromString(@"NSToolbarFullScreenWindow")]) {
+        // Check if the window that the toolbar belongs to is a Chrome App
+        // window. If it is, then don't hide it.
+        if ([window respondsToSelector:@selector(_windowForToolbar)]) {
+          NSWindow* windowForToolbar = [window _windowForToolbar];
+          SEL selector = @selector(shouldHideFullscreenToolbar);

[erikchen, 2015/11/10 08:17:22]

If you're just trying to skip the Chrome App window, why don't you just check 
the class of the window, rather than adding the method
shouldHideFullscreenToolbar?

Alternatively, it seems cleaner to whitelist the window used by this class
(FramedBrowserWindow) by checking isKindOfClass? 

[spqchan, 2015/11/10 17:14:28]

Former: I did that earlier in Patch 2, please see the earlier messages in this
CL.
Latter: Sure, if all of the windows we want to hide the toolbar for is a
FramedBrowserWindow, then I can do that. Otherwise I think having that method
would be safer.

+          if ([windowForToolbar respondsToSelector:selector] &&
+              ![windowForToolbar performSelector:selector])
+            continue;
+        }
         [[window contentView] setHidden:YES];
       }
     }