Remove unused |context| from GetDefaultParent().

chromecast/graphics/cast_window_manager_aura.cc

Index: chromecast/graphics/cast_window_manager_aura.cc
diff --git a/chromecast/graphics/cast_window_manager_aura.cc b/chromecast/graphics/cast_window_manager_aura.cc
index d0e0b7be45650bb161af085763340c35c5aa03f5..4fe2008504daaf8187544fe08cd9bb781f6900cf 100644
--- a/chromecast/graphics/cast_window_manager_aura.cc
+++ b/chromecast/graphics/cast_window_manager_aura.cc
@@ -241,8 +241,7 @@ gfx::NativeView CastWindowManagerAura::GetRootWindow() {
   return window_tree_host_->window();
 }
 
-aura::Window* CastWindowManagerAura::GetDefaultParent(aura::Window* context,
-                                                      aura::Window* window,
+aura::Window* CastWindowManagerAura::GetDefaultParent(aura::Window* window,
                                                       const gfx::Rect& bounds) {
   DCHECK(window_tree_host_);
   return window_tree_host_->window();