Improve several core/html exception messages.

This patch improves the single exception in each of:

* MediaController
* HTMLVideoElement
* HTMLTextFormControlElement
* HTMLTextAreaElement

BUG=270033

Review URL: https://codereview.chromium.org/82573003

git-svn-id: svn://svn.chromium.org/blink/trunk@162610 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: [Audits] Handle the case of empty stylesheets

Drive-by: remove unneeded bound arguments, add JsDocs

R=aandrey, eustas
BUG=322048

Review URL: https://codereview.chromium.org/83663008

git-svn-id: svn://svn.chromium.org/blink/trunk@162611 bbb929c8-8fbe-4397-9dbb-9b2b20218538