slide the title if the site changes the scroll position

Slide the title away if the scroll is to zero or one, and the
title is partially or fully visible. Set the animation time
to at least SLIDE_TITLE_DURATION, currently set to 300 ms.

core/java/android/webkit/WebView.java

@@ -420,6 +420,7 @@ public class WebView extends AbsoluteLayout
     private static final int STD_SPEED = 480;  // pixels per second
     // time for the longest scroll animation
     private static final int MAX_DURATION = 750;   // milliseconds
+    private static final int SLIDE_TITLE_DURATION = 300;   // milliseconds
     private Scroller mScroller;
 
     private boolean mWrapContent;
@@ -2416,10 +2417,18 @@ public class WebView extends AbsoluteLayout
         if ((dx | dy) == 0) {
             return false;
         }
-
-        if (true && animate) {
+        // mobile sites prefer to scroll to (0, 1), thus the + 1 below
+        boolean slideTitle = getVisibleTitleHeight() > 0
+            && y <= getTitleHeight() + 1;
+        if (DebugFlags.WEB_VIEW) {
+            Log.v(LOGTAG, "pinScrollTo slideTitle=" + slideTitle
+                    + " getVisibleTitleHeight()=" + getVisibleTitleHeight()
+                    + " animationDuration=" + animationDuration + " y=" + y);
+        }
+        if (slideTitle || animate) {
             //        Log.d(LOGTAG, "startScroll: " + dx + " " + dy);
-
+            if (slideTitle && animationDuration < SLIDE_TITLE_DURATION)
+                animationDuration = SLIDE_TITLE_DURATION;
             mScroller.startScroll(mScrollX, mScrollY, dx, dy,
                     animationDuration > 0 ? animationDuration : computeDuration(dx, dy));
             invalidate();