Added browser test for Captive Portal window ctor and dtor.

chrome/browser/chromeos/login/captive_portal_window_proxy.cc

Index: chrome/browser/chromeos/login/captive_portal_window_proxy.cc
diff --git a/chrome/browser/chromeos/login/captive_portal_window_proxy.cc b/chrome/browser/chromeos/login/captive_portal_window_proxy.cc
index 5e547a2d5fa7669a6e6e4ac2ad508d28490c11e8..c09f288c3aaea86dadf7d8279647d978ab80b376 100644
--- a/chrome/browser/chromeos/login/captive_portal_window_proxy.cc
+++ b/chrome/browser/chromeos/login/captive_portal_window_proxy.cc
@@ -90,12 +90,19 @@ void CaptivePortalWindowProxy::OnWidgetClosing(views::Widget* widget) {
   DCHECK(GetState() == STATE_DISPLAYED);
   DCHECK(widget == widget_);
 
-  widget->RemoveObserver(this);
-  widget_ = NULL;
+  DetachFromWidget(widget);
 
   DCHECK(GetState() == STATE_IDLE);
 }
 
+void CaptivePortalWindowProxy::OnWidgetDestroying(views::Widget* widget) {
+  DetachFromWidget(widget);
+}
+
+void CaptivePortalWindowProxy::OnWidgetDestroyed(views::Widget* widget) {
+  DetachFromWidget(widget);
+}
+
 void CaptivePortalWindowProxy::InitCaptivePortalView() {
   DCHECK(GetState() == STATE_IDLE ||
          GetState() == STATE_WAITING_FOR_REDIRECTION);
@@ -121,4 +128,11 @@ CaptivePortalWindowProxy::State CaptivePortalWindowProxy::GetState() const {
   return STATE_UNKNOWN;
 }
 
+void CaptivePortalWindowProxy::DetachFromWidget(views::Widget* widget) {
+  if (!widget_ || widget_ != widget)
+    return;
+  widget_->RemoveObserver(this);
+  widget_ = NULL;
+}
+
 }  // namespace chromeos