Separate PermissionsData::CanExecuteScriptOnPage into two functions

      CanExecuteScriptOnPage is currently being used for both content script
permissions and generic access (tabs api, etc).  Instead, since these have
two purposes, there should be two functions.

BUG=379356

Review URL: https://codereview.chromium.org/321533003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275568 0039d316-1c4b-4281-b951-d872f2087c98