Add test cases for panel overflow handling.

chrome/browser/notifications/balloon_collection_impl.cc

Index: chrome/browser/notifications/balloon_collection_impl.cc
diff --git a/chrome/browser/notifications/balloon_collection_impl.cc b/chrome/browser/notifications/balloon_collection_impl.cc
index 7494c7ecbe2df03890ca05c80674f7873d6c9840..062fed61cb159400b35c0d5d58d6b3ca3ef65244 100644
--- a/chrome/browser/notifications/balloon_collection_impl.cc
+++ b/chrome/browser/notifications/balloon_collection_impl.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
+#include "chrome/browser/ui/panels/panel_strip.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_service.h"
@@ -399,7 +400,8 @@ gfx::Size BalloonCollectionImpl::Layout::ConstrainToSizeLimits(
 
 bool BalloonCollectionImpl::Layout::ComputeOffsetToMoveAbovePanels(
     const gfx::Rect& panel_bounds) {
-  const PanelManager::Panels& panels = PanelManager::GetInstance()->panels();
+  const PanelManager::Panels& panels =

[jennb, 2011/12/08 23:52:00]

Use std::<vector> instead?

[jianli, 2011/12/09 22:39:07]

Done.

+      PanelManager::GetInstance()->panel_strip()->panels();

[jennb, 2011/12/08 23:52:00]

Any way to get all panels and look for any panels whose bounds overlap balloons
to reposition the balloons? Balloons need to avoid overflow panels too. 
Probably needs to be reworked in a separate patch.

[jianli, 2011/12/09 22:39:07]

I will rework on balloon interaction with overflow panels in a separate patch.

   int offset_to_move_above_panels = 0;
 
   // The offset is the maximum height of panels that could overlap with the