Promotes IsForceMaximizeOnFirstRun() to WmShell

ash/mus/bridge/wm_shell_mus.cc

Index: ash/mus/bridge/wm_shell_mus.cc
diff --git a/ash/mus/bridge/wm_shell_mus.cc b/ash/mus/bridge/wm_shell_mus.cc
index 87728714c6c3564f6c10ea0186c9a13acd5aefc1..ad6148649b1ab4a450520d8b7efb55e2ab026b7c 100644
--- a/ash/mus/bridge/wm_shell_mus.cc
+++ b/ash/mus/bridge/wm_shell_mus.cc
@@ -257,11 +257,6 @@ bool WmShellMus::IsInUnifiedModeIgnoreMirroring() const {
   return false;
 }
 
-bool WmShellMus::IsForceMaximizeOnFirstRun() {
-  NOTIMPLEMENTED();
-  return false;
-}
-
 void WmShellMus::SetDisplayWorkAreaInsets(WmWindow* window,
                                           const gfx::Insets& insets) {
   window_manager_->screen()->SetWorkAreaInsets(window->aura_window(), insets);