Update to Chromium revision 9cedf753 (#418732)

- Simplify usage of OnBeforePluginLoad (issue #2015)
- Switch crash reporting from crashpad to breakpad on Windows and OS X.
  Adds a new chrome_elf.dll dependency on Windows (issue #1995)
- Remove CefTextfield::GetPlaceholderTextColor() method which is no
  longer supported by Chromium.

libcef/renderer/dom_node_impl.cc

@@ -244,7 +244,7 @@ bool CefDOMNodeImpl::HasChildren() {
   if (!VerifyContext())
     return false;
 
-  return node_.hasChildNodes();
+  return !node_.firstChild().isNull();
 }
 
 CefRefPtr<CefDOMNode> CefDOMNodeImpl::GetFirstChild() {