Add methods needed for overflow panels to NativePanel interface.

chrome/browser/ui/panels/panel_browser_view.cc

Index: chrome/browser/ui/panels/panel_browser_view.cc
diff --git a/chrome/browser/ui/panels/panel_browser_view.cc b/chrome/browser/ui/panels/panel_browser_view.cc
index 2097753a6f3dcf5d588bb473baede3f38009ce38..3dcdbdcc4eca80d884066dcb0d7ccc17fde69ca3 100644
--- a/chrome/browser/ui/panels/panel_browser_view.cc
+++ b/chrome/browser/ui/panels/panel_browser_view.cc
@@ -377,6 +377,19 @@ void PanelBrowserView::DestroyPanelBrowser() {
   DestroyBrowser();
 }
 
+gfx::Size PanelBrowserView::GetIconifiedPanelSize() const {
+  // TODO(jianli): to be implemented.
+  return gfx::Size();
+}
+
+void PanelBrowserView::EnsurePanelFullyVisible() {
+  // TODO(jianli): to be implemented.
+}
+
+void PanelBrowserView::UpdatePanelIconInDesktopBar(PanelIconState state) {
+  // TODO(jianli): to be implemented.
+}
+
 PanelBrowserFrameView* PanelBrowserView::GetFrameView() const {
   return static_cast<PanelBrowserFrameView*>(frame()->GetFrameView());
 }