Fix the problem that notifications and panels overlap.

chrome/browser/notifications/balloon_collection_impl.h

Index: chrome/browser/notifications/balloon_collection_impl.h
diff --git a/chrome/browser/notifications/balloon_collection_impl.h b/chrome/browser/notifications/balloon_collection_impl.h
index 887d1f27ddd615d645b2cecad7817039fea837b5..049ea1124ab4e91a79b1f489447fdb9b6a8ee59b 100644
--- a/chrome/browser/notifications/balloon_collection_impl.h
+++ b/chrome/browser/notifications/balloon_collection_impl.h
@@ -16,6 +16,8 @@
 #include "base/message_loop.h"
 #include "chrome/browser/notifications/balloon_collection.h"
 #include "chrome/browser/notifications/balloon_collection_base.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 
@@ -28,11 +30,14 @@
 #define USE_OFFSETS 1
 #endif
 
+class Browser;
+
 // A balloon collection represents a set of notification balloons being
 // shown on the screen.  It positions new notifications according to
 // a layout, and monitors for balloons being closed, which it reports
 // up to its parent, the notification UI manager.
-class BalloonCollectionImpl : public BalloonCollection
+class BalloonCollectionImpl : public BalloonCollection,
+                              public content::NotificationObserver
 #if USE_OFFSETS
                             , public MessageLoopForUI::Observer
 #endif
@@ -54,6 +59,11 @@ class BalloonCollectionImpl : public BalloonCollection
   virtual void OnBalloonClosed(Balloon* source);
   virtual const Balloons& GetActiveBalloons();
 
+  // content::NotificationObserver interface.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
   // MessageLoopForUI::Observer interface.
 #if defined(OS_WIN) || defined(TOUCH_UI) || defined(USE_AURA)
   virtual base::EventStatus WillProcessEvent(
@@ -127,6 +137,10 @@ class BalloonCollectionImpl : public BalloonCollection
     // buttons under the cursor during rapid-close interaction.
     bool RequiresOffsets() const;
 
+    // Returns true if there is change to offsets. Passing |closed_browser|

[jennb, 2011/11/10 19:17:13]

s/Passing/Pass in

?

(Irrelevant if you change to using a new panel_closed notification.)

[jianli, 2011/11/11 00:38:30]

Done.

+    // if a panel is being closed.
+    bool ComputeOffsetsToMoveAbovePanels(Browser* closed_browser);
+
    private:
     // Layout parameters
     int VerticalEdgeMargin() const;
@@ -141,6 +155,13 @@ class BalloonCollectionImpl : public BalloonCollection
 
     Placement placement_;
     gfx::Rect work_area_;
+
+    // The offsets that guarantees that the notificaitons shown in the

[jennb, 2011/11/10 19:17:13]

typo: notifications

[jianli, 2011/11/11 00:38:30]

Done.

+    // bottom-right or bottom-left corner of the screen will go above currently
+    // shown panels and will not be obscured by them.
+    int bottom_left_offset_to_move_above_panels_;
+    int bottom_right_offset_to_move_above_panels_;
+
     DISALLOW_COPY_AND_ASSIGN(Layout);
   };
 
@@ -171,6 +192,8 @@ class BalloonCollectionImpl : public BalloonCollection
   // The layout parameters for balloons in this collection.
   Layout layout_;
 
+  content::NotificationRegistrar registrar_;
+
 #if USE_OFFSETS
   // Start and stop observing all UI events.
   void AddMessageLoopObserver();