Expose the selection root bounds in WebView.

public/web/WebView.h

Index: public/web/WebView.h
diff --git a/public/web/WebView.h b/public/web/WebView.h
index d4ef127e5263bf8543f2d51c5e507431cd6215ea..5d5495c125ce6bab60582bdda4de863f737a7188 100644
--- a/public/web/WebView.h
+++ b/public/web/WebView.h
@@ -472,6 +472,11 @@ public:
     virtual void setContinuousPaintingEnabled(bool) = 0;
     virtual void setShowScrollBottleneckRects(bool) = 0;
 
+    // Compute the bounds of the root element of the current selection and fills
+    // the out-parameter on success. |bounds| coordinates will be relative to
+    // the contents window and will take into account the current scale level.
+    virtual void getSelectionRootBounds(WebRect& bounds) const = 0;
+
     // Visibility -----------------------------------------------------------
 
     // Sets the visibility of the WebView.