Fix the problem that notifications and panels overlap.

chrome/browser/notifications/balloon_collection_gtk.cc

Index: chrome/browser/notifications/balloon_collection_gtk.cc
diff --git a/chrome/browser/notifications/balloon_collection_gtk.cc b/chrome/browser/notifications/balloon_collection_gtk.cc
index 2420735f72016bcb90b005615545ae8ed5203de6..5b8a7848b2cf8504faf9e74e2a3f08ac02adef7a 100644
--- a/chrome/browser/notifications/balloon_collection_gtk.cc
+++ b/chrome/browser/notifications/balloon_collection_gtk.cc
@@ -35,6 +35,14 @@ int BalloonCollectionImpl::Layout::VerticalEdgeMargin() const {
   return 5;
 }
 
+bool BalloonCollectionImpl::Layout::NeedToMoveAboveLeftSidePanels() const {
+  return placement_ == VERTICALLY_FROM_BOTTOM_LEFT;
+}
+
+bool BalloonCollectionImpl::Layout::NeedToMoveAboveRightSidePanels() const {
+  return placement_ == VERTICALLY_FROM_BOTTOM_RIGHT;
+}
+
 void BalloonCollectionImpl::PositionBalloons(bool reposition) {
   PositionBalloonsInternal(reposition);
 }
@@ -92,6 +100,7 @@ void BalloonCollectionImpl::SetPositionPreference(
   else
     NOTREACHED();
 
+  layout_.ComputeOffsetToMoveAbovePanels(gfx::Rect());
   PositionBalloons(true);
 }