Bug 618975 Mobile patch r=mfinkle a=blocking-fennec

mobile/chrome/content/bindings/browser.js

@@ -301,11 +301,18 @@ let ContentScroll =  {
   },
 
   getScrollOffsetForElement: function(aElement) {
+    if (aElement.parentNode == aElement.ownerDocument)
       return this.getScrollOffset(aElement.ownerDocument.defaultView);
+    return { x: aElement.scrollLeft, y: aElement.scrollTop };
   },
 
   setScrollOffsetForElement: function(aElement, aLeft, aTop) {
+    if (aElement.parentNode == aElement.ownerDocument) {
       aElement.ownerDocument.defaultView.scrollTo(aLeft, aTop);
+    } else {
+      aElement.scrollLeft = aLeft;
+      aElement.scrollTop = aTop;
+    }
   },
 
   receiveMessage: function(aMessage) {
@@ -347,7 +354,8 @@ let ContentScroll =  {
 
         let win = element.ownerDocument.defaultView;
         let winCwu = win.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
-        winCwu.setDisplayPort(x, y, displayport.width, displayport.height);
+        let winCwu20 = winCwu.QueryInterface(Ci.nsIDOMWindowUtils_MOZILLA_2_0_BRANCH);
+        winCwu20.setDisplayPortForElement(x, y, displayport.width, displayport.height, element);
 
         break;
       }
@@ -419,7 +427,8 @@ let ContentActive =  {
       case "Content:Deactivate":
         docShell.isActive = false;
         let cwu = content.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
-        cwu.setDisplayPort(0,0,0,0);
+        let cwu20 = cwu.QueryInterface(Ci.nsIDOMWindowUtils_MOZILLA_2_0_BRANCH);
+        cwu20.setDisplayPortForElement(0,0,0,0,content.document.documentElement);
         break;
 
       case "Content:Activate":

mobile/chrome/content/bindings/browser.xml

@@ -950,7 +950,13 @@
            */
           _updateCacheViewport: function() {
             // Do not update scroll values for content.
+            if (this.isRoot())
               this._sendDisplayportUpdate(-1, -1);
+            else {
+              let contentView = this._contentView;
+              this._sendDisplayportUpdate(contentView.scrollX,
+                                          contentView.scrollY);
+            }
           },
 
           _getContentSize: function() {

mobile/chrome/content/browser.js

@@ -1161,6 +1161,8 @@ Browser.MainDragger.prototype = {
   },
 
   dragStop: function dragStop(dx, dy, scroller) {
+    if (this._contentView && this._contentView._updateCacheViewport)
+      this._contentView._updateCacheViewport();
     this._contentView = null;
     this.dragMove(Browser.snapSidebars(), 0, scroller);
     Browser.tryUnfloatToolbar();