Converts MessagePopupCollection into a long-lived object.

This improves the behavior since there were several scenarios where
observer methods would cause re-entrancy into the destructor of
MessagePopupCollection. Since it observes MessageCenter, it knows when
it should show popups and when it shouldn't.

This CL is based on dewittj's crrev.com/114553002 with a fix
for some tests in linux-aura and win because of screen_aura.

BUG=327363
R=dewittj@chromium.org, stevenjb@chromium.org

Review URL: https://codereview.chromium.org/180513002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254101 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 28 insertions, 23 deletions

diff --git a/ui/message_center/views/message_popup_collection.cc b/ui/message_center/views/message_popup_collection.cc
index bc2da0c..2039d49 100644
--- a/ui/message_center/views/message_popup_collection.cc
+++ b/ui/message_center/views/message_popup_collection.cc
@@ -65,6 +65,8 @@ MessagePopupCollection::MessagePopupCollection(gfx::NativeView parent,
     : parent_(parent),
       message_center_(message_center),
       tray_(tray),
+      display_id_(gfx::Display::kInvalidDisplayID),
+      screen_(NULL),
       defer_counter_(0),
       latest_toast_entered_(NULL),
       user_is_closing_toasts_by_clicking_(false),
@@ -74,34 +76,13 @@ MessagePopupCollection::MessagePopupCollection(gfx::NativeView parent,
   DCHECK(message_center_);
   defer_timer_.reset(new base::OneShotTimer<MessagePopupCollection>);
   message_center_->AddObserver(this);
-  gfx::Screen* screen = NULL;
-  gfx::Display display;
-  if (!parent_) {
-    // On Win+Aura, we don't have a parent since the popups currently show up
-    // on the Windows desktop, not in the Aura/Ash desktop.  This code will
-    // display the popups on the primary display.
-    screen = gfx::Screen::GetNativeScreen();
-    display = screen->GetPrimaryDisplay();
-  } else {
-    screen = gfx::Screen::GetScreenFor(parent_);
-    display = screen->GetDisplayNearestWindow(parent_);
-  }
-  screen->AddObserver(this);
-
-  display_id_ = display.id();
-  work_area_ = display.work_area();
-  ComputePopupAlignment(work_area_, display.bounds());
-
-  // We should not update before work area and popup alignment are computed.
-  DoUpdateIfPossible();
 }
 
 MessagePopupCollection::~MessagePopupCollection() {
   weak_factory_.InvalidateWeakPtrs();
 
-  gfx::Screen* screen = parent_ ?
-      gfx::Screen::GetScreenFor(parent_) : gfx::Screen::GetNativeScreen();
-  screen->RemoveObserver(this);
+  if (screen_)
+    screen_->RemoveObserver(this);
   message_center_->RemoveObserver(this);
 
   CloseAllWidgets();
@@ -525,6 +506,25 @@ void MessagePopupCollection::DecrementDeferCounter() {
 // deferred tasks are even able to run)
 // Then, see if there is vacant space for new toasts.
 void MessagePopupCollection::DoUpdateIfPossible() {
+  if (!screen_) {
+    gfx::Display display;
+    if (!parent_) {
+      // On Win+Aura, we don't have a parent since the popups currently show up
+      // on the Windows desktop, not in the Aura/Ash desktop.  This code will
+      // display the popups on the primary display.
+      screen_ = gfx::Screen::GetNativeScreen();
+      display = screen_->GetPrimaryDisplay();
+    } else {
+      screen_ = gfx::Screen::GetScreenFor(parent_);
+      display = screen_->GetDisplayNearestWindow(parent_);
+    }
+    screen_->AddObserver(this);
+
+    display_id_ = display.id();
+    work_area_ = display.work_area();
+    ComputePopupAlignment(work_area_, display.bounds());
+  }
+
   if (defer_counter_ > 0)
     return;
 
diff --git a/ui/message_center/views/message_popup_collection.h b/ui/message_center/views/message_popup_collection.h
index 6586b41..907274e 100644
--- a/ui/message_center/views/message_popup_collection.h
+++ b/ui/message_center/views/message_popup_collection.h
@@ -35,6 +35,10 @@ class WebNotificationTrayTest;
 FORWARD_DECLARE_TEST(WebNotificationTrayTest, ManyPopupNotifications);
 }
 
+namespace gfx {
+class Screen;
+}
+
 namespace message_center {
 namespace test {
 class MessagePopupCollectionTest;
@@ -184,6 +188,7 @@ class MESSAGE_CENTER_EXPORT MessagePopupCollection
   Toasts toasts_;
   gfx::Rect work_area_;
   int64 display_id_;
+  gfx::Screen* screen_;
 
   // Specifies which corner of the screen popups should show up. This should
   // ideally be the same corner the notification area (systray) is at.