Revert of Converts MessagePopupCollection into a long-lived object. (https://codereview.chromium.org/180513002/)

Reason for revert:
Possible cause of build breakage:

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/40180

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/40180/steps/message_center_unittests/logs/LeftPositioningWithLeftTaskbar

MessagePopupCollectionTest.LeftPositioningWithLeftTaskbar (run #1):
[ RUN      ] MessagePopupCollectionTest.LeftPositioningWithLeftTaskbar
Xlib:  extension "RANDR" missing on display ":9".
../../ui/message_center/views/message_popup_collection_unittest.cc:341: Failure
Expected: (r1.x()) \u003C (GetWorkArea().CenterPoint().x()), actual: 433 vs 400
[  FAILED  ] MessagePopupCollectionTest.LeftPositioningWithLeftTaskbar (430 ms)


Original issue's description:
> 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
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254101

TBR=dewittj@chromium.org,stevenjb@chromium.org,mukai@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=327363

Review URL: https://codereview.chromium.org/183883006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254145 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 23 insertions, 28 deletions

diff --git a/ui/message_center/views/message_popup_collection.cc b/ui/message_center/views/message_popup_collection.cc
index 2039d49..bc2da0c 100644
--- a/ui/message_center/views/message_popup_collection.cc
+++ b/ui/message_center/views/message_popup_collection.cc
@@ -65,8 +65,6 @@ 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),
@@ -76,13 +74,34 @@ 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();
 
-  if (screen_)
-    screen_->RemoveObserver(this);
+  gfx::Screen* screen = parent_ ?
+      gfx::Screen::GetScreenFor(parent_) : gfx::Screen::GetNativeScreen();
+  screen->RemoveObserver(this);
   message_center_->RemoveObserver(this);
 
   CloseAllWidgets();
@@ -506,25 +525,6 @@ 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 907274e..6586b41 100644
--- a/ui/message_center/views/message_popup_collection.h
+++ b/ui/message_center/views/message_popup_collection.h
@@ -35,10 +35,6 @@ class WebNotificationTrayTest;
 FORWARD_DECLARE_TEST(WebNotificationTrayTest, ManyPopupNotifications);
 }
 
-namespace gfx {
-class Screen;
-}
-
 namespace message_center {
 namespace test {
 class MessagePopupCollectionTest;
@@ -188,7 +184,6 @@ 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.