Fix setting action bar home-as-up from AB style

Bug 6427860

Change-Id: I0052417a2c97560ade768509781b27b5e064660d

Author: adamp

core/java/com/android/internal/app/ActionBarImpl.java

@@ -184,8 +184,15 @@ private void init(View decor) {
         mContextDisplayMode = mActionView.isSplitActionBar() ?
                 CONTEXT_DISPLAY_SPLIT : CONTEXT_DISPLAY_NORMAL;
 
+        // This was initially read from the action bar style
+        final int current = mActionView.getDisplayOptions();
+        final boolean homeAsUp = (current & DISPLAY_HOME_AS_UP) != 0;
+        if (homeAsUp) {
+            mDisplayHomeAsUpSet = true;
+        }
+
         ActionBarPolicy abp = ActionBarPolicy.get(mContext);
-        setHomeButtonEnabled(abp.enableHomeButtonByDefault());
+        setHomeButtonEnabled(abp.enableHomeButtonByDefault() || homeAsUp);
         setHasEmbeddedTabs(abp.hasEmbeddedTabs());
     }