PluginDocument should use AttachLazily

Use AttachLazily in all the appendChild calls in PluginDocument.

This doesn't really result in a real behavior change since PluginDocumentParser
calls updateLayout() right after appending the nodes so it can grab back the
Widget to pipe the stream of data off the network directly into the plugin.

Review URL: https://chromiumcodereview.appspot.com/22999028

git-svn-id: svn://svn.chromium.org/blink/trunk@156411 bbb929c8-8fbe-4397-9dbb-9b2b20218538
InputType::destroyShadowSubtree should AttachLazily

destroyShadowSubtree adds <shadow> elements to support the extra ShadowRoot
added by PasswordGeneratorButtonElement, we should lazy attach these. Eventually
we should just remove that extra shadow root hack though.

TBR=eseidel@chromium.org
BUG=276687

Review URL: https://chromiumcodereview.appspot.com/23201014

git-svn-id: svn://svn.chromium.org/blink/trunk@156412 bbb929c8-8fbe-4397-9dbb-9b2b20218538