aura: Do not attempt to remove the window multiple times on detach.

The window gets removed in RemovedFromWidget, so it is not necessary to do
this again in NativeViewDetaching. This fixes a couple of failing DOMViewTest
tests.

BUG=103487
TEST=DOMViewTest.TestRemoveAndDelete, TestReparent (browser_tests)

Review URL: http://codereview.chromium.org/8574016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110198 0039d316-1c4b-4281-b951-d872f2087c98

views/controls/native/native_view_host_aura.cc

@@ -35,7 +35,6 @@ void NativeViewHostAura::NativeViewDetaching(bool destroyed) {
   if (!destroyed) {
     host_->native_view()->RemoveObserver(this);
     host_->native_view()->Hide();
-    host_->GetWidget()->GetNativeView()->RemoveChild(host_->native_view());
   }
 }