[webkit-reviews] review requested: [Bug 28689] Replace disabled media mute button with port-specific implementation. : [Attachment 39900] Second attempt

[bugzilla-daemon at webkit.org]

Andrew Scherkus <scherkus at chromium.org> has asked  for review:
Bug 28689: Replace disabled media mute button with port-specific
implementation.
https://bugs.webkit.org/show_bug.cgi?id=28689

Attachment 39900: Second attempt
https://bugs.webkit.org/attachment.cgi?id=39900&action=review

------- Additional Comments from Andrew Scherkus <scherkus at chromium.org>
This is a draft of deferring the decision on rendering a media control element
to the RenderTheme.

This is my first real dive into Element/RenderObject/Style/Theme interaction,
so feel free to point out my mistakes :)

The overall change is:
 1) Media control elements will always create a renderer
 2) RenderTheme decides whether those renderers will be visible based on
inspecting the HTMLMediaElement