Expose the selection root bounds in WebView.

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 822 matching lines @@
     m_client->scheduleAnimation();
 }
 
 void WebViewImpl::setShowScrollBottleneckRects(bool show)
 {
     if (m_layerTreeView)
         m_layerTreeView->setShowScrollBottleneckRects(show);
     m_showScrollBottleneckRects = show;
 }
 
+void WebViewImpl::getSelectionRootBounds(WebRect& bounds) const
+{
+    const LocalFrame* frame = focusedWebCoreFrame();
+    if (!frame)
+        return;
+
+    Element* root = frame->selection().rootEditableElementOrDocumentElement();
+    if (!root)
+        return;
+
+    // If the selection is inside a form control, the root will be a <div> that
+    // behaves as the editor but we want to return the actual element's bounds.
+    // In practice, that means <textarea> and <input> controls that behave like
+    // a text field.

[jamesr, 2014/03/11 21:58:39]

this seems reasonable it's a bit subtle - you need some tests to make sure that
this is doing what you want.

+    Element* shadowHost = root->shadowHost();
+    if (shadowHost
+        && (shadowHost->hasTagName(HTMLNames::textareaTag)
+            || (shadowHost->hasTagName(HTMLNames::inputTag)
+                && toHTMLInputElement(shadowHost)->isText())))
+        root = shadowHost;
+
+    IntRect boundingBox = root->pixelSnappedBoundingBox();
+    boundingBox = root->document().frame()->view()->contentsToWindow(boundingBox);
+    boundingBox.scale(pageScaleFactor());
+    bounds = boundingBox;
+}
+
 bool WebViewImpl::handleKeyEvent(const WebKeyboardEvent& event)
 {
     ASSERT((event.type == WebInputEvent::RawKeyDown)
         || (event.type == WebInputEvent::KeyDown)
         || (event.type == WebInputEvent::KeyUp));
 
     // Halt an in-progress fling on a key event.
     endActiveFlingAnimation();
 
     // Please refer to the comments explaining the m_suppressNextKeypressEvent
@@ skipping 3115 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink