Merge pull request openlayers#351 from elemoine/pinch2

After great sleuthing from @elemoine, we have a solution closer to the heart of the problem.  In a funny twist, the excessive call to `updateSize` ended up hinting at the solution.  Thanks to `git bisect` for making things a bit easier.

Author: tschaub

lib/OpenLayers/Control/PinchZoom.js

@@ -184,6 +184,20 @@ OpenLayers.Control.PinchZoom = OpenLayers.Class(OpenLayers.Control, {
             location.lon += resolution * ((size.w / 2) - zoomPixel.x);
             location.lat -= resolution * ((size.h / 2) - zoomPixel.y);
 
+            // Force a reflow before calling setCenter. This is to work
+            // around an issue occuring in iOS.
+            //
+            // See https://github.com/openlayers/openlayers/pull/351.
+            //
+            // Without a reflow setting the layer container div's top left
+            // style properties to "0px" - as done in Map.moveTo when zoom
+            // is changed - won't actually correctly reposition the layer
+            // container div.
+            //
+            // Also, we need to use a statement that the Google Closure
+            // compiler won't optimize away.
+            this.map.div.clientWidth = this.map.div.clientWidth;
+
             this.map.setCenter(location, zoom);
         }
     },