Use the pinch viewport offset for tap disambiguation.

public/web/WebViewClient.h

Index: public/web/WebViewClient.h
diff --git a/public/web/WebViewClient.h b/public/web/WebViewClient.h
index bc0bb7edf1af646efd89055f61af4171e0399921..ce21d7d4bf2a8dc3cdda04a1278e0817f9fe7380 100644
--- a/public/web/WebViewClient.h
+++ b/public/web/WebViewClient.h
@@ -204,9 +204,15 @@ public:
     // unless the view did not need a layout.
     virtual void didUpdateLayout() { }
 
+    // TODO: This is a deprecated method. Remove it after the chromium change

[jamesr, 2014/09/23 23:25:16]

s/TODO/FIXME/

+    // that uses the second didTapMultipleTargets() propagates.
+    //
     // Return true to swallow the input event if the embedder will start a disambiguation popup
     virtual bool didTapMultipleTargets(const WebGestureEvent&, const WebVector<WebRect>& targetRects) { return false; }
 
+    // Return true to swallow the input event if the embedder will start a disambiguation popup
+    virtual bool didTapMultipleTargets(const WebSize& pinchViewportOffset, const WebRect& touchRect, const WebVector<WebRect>& targetRects) { return false; }
+
     // Returns comma separated list of accept languages.
     virtual WebString acceptLanguages() { return WebString(); }