In ActionBarImpl, only use mActionView after we've checked that it's non-null

See https://android-git.corp.google.com/g/#change,61251

Change-Id: Ie11f446c10c096916642a34558a350512495234e
diff --git a/core/java/com/android/internal/app/ActionBarImpl.java b/core/java/com/android/internal/app/ActionBarImpl.java
index ef0ab41..1048352 100644
--- a/core/java/com/android/internal/app/ActionBarImpl.java
+++ b/core/java/com/android/internal/app/ActionBarImpl.java
@@ -110,13 +110,13 @@
                 com.android.internal.R.id.lower_action_context_bar);
         mAnimatorView = (ViewAnimator) decor.findViewById(
                 com.android.internal.R.id.action_bar_animator);
-        mActionView.setContextView(mUpperContextView);
-        
+
         if (mActionView == null || mUpperContextView == null || mAnimatorView == null) {
             throw new IllegalStateException(getClass().getSimpleName() + " can only be used " +
                     "with a compatible window decor layout");
         }
 
+        mActionView.setContextView(mUpperContextView);
         mContextDisplayMode = mLowerContextView == null ?
                 CONTEXT_DISPLAY_NORMAL : CONTEXT_DISPLAY_SPLIT;
     }