Split out fullscreen logic from Browser into FullscreenController.

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 5caeb75b6c70efcc1036e567355e1a9d375e5cc0..4617ebe76255b46c3c7552d2710dabf005a488b7 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -672,7 +672,7 @@ willPositionSheet:(NSWindow*)sheet
     return;
 
   if (presentationMode) {
-    BOOL fullscreen_for_tab = browser_->is_fullscreen_for_tab();
+    BOOL fullscreen_for_tab = browser_->IsFullscreenForTab();
     BOOL showDropdown = !fullscreen_for_tab &&
         (forceDropdown || [self floatingBarHasFocus]);
     NSView* contentView = [[self window] contentView];
@@ -785,7 +785,7 @@ willPositionSheet:(NSWindow*)sheet
 }
 
 - (void)showFullscreenExitBubbleIfNecessary {
-  if (!browser_->is_fullscreen_for_tab()) {
+  if (!browser_->IsFullscreenForTab()) {
     return;
   }
 
@@ -847,7 +847,7 @@ willPositionSheet:(NSWindow*)sheet
   NSWindow* window = [self window];
   savedRegularWindowFrame_ = [window frame];
   BOOL mode = [self shouldUsePresentationModeWhenEnteringFullscreen];
-  mode = mode || browser_->is_fullscreen_for_tab();
+  mode = mode || browser_->IsFullscreenForTab();
   [self setPresentationModeInternal:mode forceDropdown:NO];
 }