delete chrome.experimental.identity

BUG=304836

Review URL: https://codereview.chromium.org/102963002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238749 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238749
Prevent the browser process from creating duplicate RenderWidgetHosts

This is a follow up CL for crrev.com/238575. The same problem exists when creating RenderWidgetHosts and this CL address this.

BUG=312016

Review URL: https://codereview.chromium.org/105033002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238750 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238750