Fix showing constrained window for uninitialized tabs

chrome/browser/ui/cocoa/constrained_window/constrained_window_mac2.mm

 // Copyright (c) 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.
 
 #include "chrome/browser/ui/cocoa/constrained_window/constrained_window_mac2.h"
 
 #include "base/logging.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/cocoa/constrained_window/constrained_window_sheet_controller.h"
 #include "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
 #include "chrome/browser/ui/constrained_window_tab_helper.h"
+#include "content/public/browser/notification_source.h"
+#include "content/public/browser/notification_types.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 
 ConstrainedWindowMac2::ConstrainedWindowMac2(
     ConstrainedWindowMacDelegate2* delegate,
     content::WebContents* web_contents,
     NSWindow* window)
     : delegate_(delegate),
       web_contents_(web_contents),
-      window_([window retain]) {
+      window_([window retain]),
+      pending_show_(false) {
   DCHECK(web_contents);
   DCHECK(window_.get());
   ConstrainedWindowTabHelper* constrained_window_tab_helper =
       ConstrainedWindowTabHelper::FromWebContents(web_contents);
   constrained_window_tab_helper->AddConstrainedDialog(this);
+
+  registrar_.Add(this,
+                 content::NOTIFICATION_WEB_CONTENTS_VISIBILITY_CHANGED,
+                 content::Source<content::WebContents>(web_contents));
 }
 
 ConstrainedWindowMac2::~ConstrainedWindowMac2() {
 }
 
 void ConstrainedWindowMac2::ShowConstrainedWindow() {
   NSWindow* parent_window = GetParentWindow();
-  if (!parent_window)
+  NSView* parent_view = GetSheetParentViewForWebContents(web_contents_);
+  if (!parent_window || !parent_view) {
+    pending_show_ = true;
     return;
-
-  NSView* parent_view = GetSheetParentViewForWebContents(web_contents_);
-  DCHECK(parent_view);
+  }
 
   ConstrainedWindowSheetController* controller =
       [ConstrainedWindowSheetController
           controllerForParentWindow:parent_window];
   [controller showSheet:window_ forParentView:parent_view];
 }
 
 void ConstrainedWindowMac2::CloseConstrainedWindow() {
+  // This function may be called even if the constrained window was never shown.
+  // Unset |pending_show_| to prevent the window from being reshown.
+  pending_show_ = false;
+
   [[ConstrainedWindowSheetController controllerForSheet:window_]
       closeSheet:window_];
   ConstrainedWindowTabHelper* constrained_window_tab_helper =
       ConstrainedWindowTabHelper::FromWebContents(web_contents_);
   constrained_window_tab_helper->WillClose(this);
   if (delegate_)
     delegate_->OnConstrainedWindowClosed(this);
 }
 
 void ConstrainedWindowMac2::PulseConstrainedWindow() {
   [[ConstrainedWindowSheetController controllerForSheet:window_]
       pulseSheet:window_];
 }
 
 gfx::NativeWindow ConstrainedWindowMac2::GetNativeWindow() {
   return window_;
 }
 
 bool ConstrainedWindowMac2::CanShowConstrainedWindow() {
   Browser* browser = browser::FindBrowserWithWebContents(web_contents_);
   if (!browser)
     return true;
   return !browser->window()->IsInstantTabShowing();
 }
 
+void ConstrainedWindowMac2::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  if (type != content::NOTIFICATION_WEB_CONTENTS_VISIBILITY_CHANGED) {
+    NOTREACHED();
+    return;
+  }
+
+  if (pending_show_) {
+    pending_show_ = false;
+    ShowConstrainedWindow();
+  }
+}
+
 NSWindow* ConstrainedWindowMac2::GetParentWindow() const {
   // Tab contents in a tabbed browser may not be inside a window. For this
   // reason use a browser window if possible.
   Browser* browser = browser::FindBrowserWithWebContents(web_contents_);
   if (browser)
     return browser->window()->GetNativeWindow();
 
   return web_contents_->GetView()->GetTopLevelNativeWindow();
 }