DO NOT MERGE Using Activity#setTitle to have TalkBack announce root

traversal.

Bug: 32260739
Bug: 28275570
Change-Id: Ie3711e8ccbf588838a3f21346f317243516382bd

packages/DocumentsUI/src/com/android/documentsui/BaseActivity.java

@@ -387,6 +387,12 @@ public abstract class BaseActivity extends Activity
         }
 
         mNavigator.update();
+        // Causes talkback to announce the activity's new title
+        if (mState.stack.isRecents()) {
+            setTitle(mRoots.getRecentsRoot().title);
+        } else {
+            setTitle(mState.stack.getTitle());
+        }
         invalidateOptionsMenu();
     }
 

packages/DocumentsUI/src/com/android/documentsui/FilesActivity.java

@@ -192,7 +192,7 @@ public class FilesActivity extends BaseActivity {
         Intent intent = getIntent();
         return (intent != null && intent.hasExtra(Intent.EXTRA_TITLE))
                 ? intent.getStringExtra(Intent.EXTRA_TITLE)
-                : getTitle().toString();
+                : getString(R.string.downloads_label);
     }
 
     @Override