Fix Mac password bubble crash due to the "nope" menu hanging around.

By default open menus in Cocoa exist until the user makes a choice, but
since the bubble and its backing controller are owned and managed by
cross-platform code, this model doesn't make sense. Hiding the menu
programmatically matches the Views implementation and fixes the crash.

Since triggering the NSPopUpButton's menu with |performClick:| spins
a run loop waiting for user input, getting a test working was extremely
difficult. The solution is to refactor BubbleCombobox to subclass
MenuButton instead of NSPopUpButton; http://crbug.com/415088 created
to track this work, which will then support a test for this bug.

BUG=413267

Review URL: https://codereview.chromium.org/563093003

Cr-Commit-Position: refs/heads/master@{#296398}

chrome/browser/ui/cocoa/passwords/manage_passwords_bubble_content_view_controller.h

@@ -32,6 +32,7 @@ const CGFloat kUnrelatedControlVerticalPadding = 20;
 - (NSButton*)addButton:(NSString*)title target:(id)target action:(SEL)action;
 - (NSTextField*)addTitleLabel:(NSString*)title;
 - (NSTextField*)addLabel:(NSString*)title;
+- (void)bubbleWillDisappear;
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_PASSWORDS_MANAGE_PASSWORDS_BUBBLE_CONTENT_VIEW_CONTROLLER_H_

chrome/browser/ui/cocoa/passwords/manage_passwords_bubble_content_view_controller.mm

@@ -43,4 +43,7 @@
   return label;
 }
 
+- (void)bubbleWillDisappear {
+}
+
 @end

chrome/browser/ui/cocoa/passwords/manage_passwords_bubble_controller.h

@@ -23,7 +23,8 @@
                            ManagePasswordsBubblePendingViewDelegate> {
  @private
   ManagePasswordsBubbleModel* model_;
-  base::scoped_nsobject<NSViewController> currentController_;
+  base::scoped_nsobject<ManagePasswordsBubbleContentViewController>
+      currentController_;
 }
 - (id)initWithParentWindow:(NSWindow*)parentWindow
                      model:(ManagePasswordsBubbleModel*)model;

chrome/browser/ui/cocoa/passwords/manage_passwords_bubble_controller.mm

@@ -42,6 +42,11 @@
   [super showWindow:sender];
 }
 
+- (void)close {
+  [currentController_ bubbleWillDisappear];
+  [super close];
+}
+
 - (void)updateState {
   // Find the next view controller.
   currentController_.reset();

chrome/browser/ui/cocoa/passwords/manage_passwords_bubble_pending_view_controller.mm

@@ -35,6 +35,13 @@ using namespace password_manager::mac::ui;
   return self;
 }
 
+- (void)bubbleWillDisappear {
+  // The "nope" drop-down won't be dismissed until the user chooses an option,
+  // but if the bubble is dismissed (by cross-platform code) before the user
+  // makes a choice, then the choice won't actually take any effect.
+  [[nopeButton_ menu] cancelTrackingWithoutAnimation];
+}
+
 - (void)onSaveClicked:(id)sender {
   model_->OnSaveClicked();
   [delegate_ viewShouldDismiss];