Fix the full screen switching browser window dipping below launcher bar issue.

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index aaec097a2fb4b4fe7d832b936de9a0e986aeea4b..2db8af3234b4994ae8e208377d58c2b4371e8e31 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -115,6 +115,14 @@ gfx::Size RootWindow::GetHostSize() const {
   return rect.size();
 }
 
+void RootWindow::SetScreenWorkAreaInsets(const gfx::Insets& insets) {
+  if (screen_->work_area_insets() == insets)
+    return;
+  screen_->set_work_area_insets(insets);
+  FOR_EACH_OBSERVER(RootWindowObserver, observers_,
+                    OnScreenWorkAreaInsetsChanged());
+}
+
 void RootWindow::SetCursor(gfx::NativeCursor cursor) {
   last_cursor_ = cursor;
   // A lot of code seems to depend on NULL cursors actually showing an arrow,