Titlebar Autoshow tweaks

 Also consolidate some common code between phone and tablet

Change-Id: I2e1be9be84b07726596d4b4fe7345c0074236be1
diff --git a/src/com/android/browser/BaseUi.java b/src/com/android/browser/BaseUi.java
index f7d7a3c..ad45958 100644
--- a/src/com/android/browser/BaseUi.java
+++ b/src/com/android/browser/BaseUi.java
@@ -857,13 +857,14 @@
     @Override
     public void onScroll(int visibleTitleHeight, boolean userInitiated) {
         WebView view = mActiveTab != null ? mActiveTab.getWebView() : null;
-        if (view == null || !userInitiated) {
+        if (view == null) {
             return;
         }
         int scrollY = view.getScrollY();
-        if (scrollY < (mLastScrollY - mTitlebarScrollTriggerSlop)) {
+        if (isTitleBarShowing()
+                || scrollY < (mLastScrollY - mTitlebarScrollTriggerSlop)) {
             mLastScrollY = scrollY;
-            if (visibleTitleHeight == 0) {
+            if (visibleTitleHeight == 0 && userInitiated) {
                 mHandler.removeMessages(MSG_HIDE_TITLEBAR);
                 showTitleBar();
                 Message msg = Message.obtain(mHandler, MSG_HIDE_TITLEBAR);