Add Panel::SetPanelBoundsInstantly for all platforms.

chrome/browser/ui/panels/panel_browser_window_gtk.cc

Index: chrome/browser/ui/panels/panel_browser_window_gtk.cc
diff --git a/chrome/browser/ui/panels/panel_browser_window_gtk.cc b/chrome/browser/ui/panels/panel_browser_window_gtk.cc
index 68db6feace21e62f2c04fa2fd871e9da16f905d8..f3a856e301f9de9eeada07ad8510f09d290e00c6 100644
--- a/chrome/browser/ui/panels/panel_browser_window_gtk.cc
+++ b/chrome/browser/ui/panels/panel_browser_window_gtk.cc
@@ -244,11 +244,12 @@ gfx::Rect PanelBrowserWindowGtk::GetPanelBounds() const {
   return bounds_;
 }
 
-void PanelBrowserWindowGtk::SetPanelBounds(const gfx::Rect& bounds) {
+void PanelBrowserWindowGtk::SetPanelBounds(const gfx::Rect& bounds,
+                                           bool animate) {
   if (bounds == bounds_)
     return;
 
-  if (drag_widget_) {
+  if (drag_widget_ || !animate) {
     DCHECK(!bounds_animator_.get() || !bounds_animator_->is_animating());
     // If the current panel is being dragged, it should just move with the
     // user drag, we should not animate.