Fix TabHost stealing focus on hardware keyboard keypress

Don't try to change focus at all on exit from touch mode. The old
behavior might have been useful for very old apps with a TabHost as
their primary UI, but that's not a modern app structure.

Bug: 21417491
Change-Id: I3db2ab42c90b6c82f23216244a8183c4290eb7d7

core/java/android/widget/TabHost.java

@@ -188,32 +188,9 @@ mTabHost.addTab(TAB_TAG_1, "Hello, world!", "Tab 1");
         mLocalActivityManager = activityGroup;
     }
 
-
     @Override
-    protected void onAttachedToWindow() {
-        super.onAttachedToWindow();
-        final ViewTreeObserver treeObserver = getViewTreeObserver();
-        treeObserver.addOnTouchModeChangeListener(this);
-    }
-
-    @Override
-    protected void onDetachedFromWindow() {
-        super.onDetachedFromWindow();
-        final ViewTreeObserver treeObserver = getViewTreeObserver();
-        treeObserver.removeOnTouchModeChangeListener(this);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
     public void onTouchModeChanged(boolean isInTouchMode) {
-        if (!isInTouchMode) {
-            // leaving touch mode.. if nothing has focus, let's give it to
-            // the indicator of the current tab
-            if (mCurrentView != null && (!mCurrentView.hasFocus() || mCurrentView.isFocused())) {
-                mTabWidget.getChildTabViewAt(mCurrentTab).requestFocus();
-            }
-        }
+        // No longer used, but kept to maintain API compatibility.
     }
 
     /**