Simplify fullscreen exit bubble on mac; updating always creates one freshly.

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 f517536883babc34b8878eb15cc53ba6722a938c..333a24bcff2efa9705d984c3fb41b6e02422bf51 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -793,14 +793,20 @@ willPositionSheet:(NSWindow*)sheet
 - (void)showFullscreenExitBubbleIfNecessary {
   [presentationModeController_ ensureOverlayHiddenWithAnimation:NO delay:NO];
 
-  [fullscreenExitBubbleController_ closeImmediately];
-  fullscreenExitBubbleController_.reset(
-      [[FullscreenExitBubbleController alloc]
-          initWithOwner:self
-                browser:browser_.get()
-                    url:fullscreenUrl_
-             bubbleType:fullscreenBubbleType_]);
-  [fullscreenExitBubbleController_ showWindow];
+  if (fullscreenBubbleType_ == FEB_TYPE_NONE ||
+      fullscreenBubbleType_ == FEB_TYPE_BROWSER_FULLSCREEN_EXIT_INSTRUCTION) {
+    // Show no exit instruction bubble on Mac when in Browser Fullscreen.
+    [self destroyFullscreenExitBubbleIfNecessary];
+  } else {
+    [fullscreenExitBubbleController_ closeImmediately];
+    fullscreenExitBubbleController_.reset(
+        [[FullscreenExitBubbleController alloc]
+            initWithOwner:self
+                  browser:browser_.get()
+                      url:fullscreenUrl_
+               bubbleType:fullscreenBubbleType_]);
+    [fullscreenExitBubbleController_ showWindow];
+  }
 }
 
 - (void)destroyFullscreenExitBubbleIfNecessary {