Coverity: Initialize instance_id_ in the constructor.

CID=6212
BUG=none
TEST=none
Review URL: http://codereview.chromium.org/208051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@26858 0039d316-1c4b-4281-b951-d872f2087c98

chrome/renderer/webplugin_delegate_proxy.cc

@@ -163,6 +163,7 @@ WebPluginDelegateProxy::WebPluginDelegateProxy(
       windowless_(false),
       window_(NULL),
       mime_type_(mime_type),
+      instance_id_(MSG_ROUTING_NONE),
       npobject_(NULL),
       window_script_object_(NULL),
       sad_plugin_(NULL),