Add a command line flag (--enable-fixed-position-compositing) for enabling compositing

Add a command line flag (--enable-fixed-position-compositing) for enabling compositing
of fixed position elements.

BUG=None
TEST=Manual testing to verify the flag works.
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=108166

[vangelis, 2011-10-27 05:58:12]

Please review. 

This CL must land after https://bugs.webkit.org/show_bug.cgi?id=69796 is checked
in and the DEPS are rolled.

[jamesr, 2011-10-27 06:19:52]

lgtm

http://codereview.chromium.org/8404026/diff/1/content/browser/renderer_host/b...
File content/browser/renderer_host/browser_render_process_host.cc (right):

http://codereview.chromium.org/8404026/diff/1/content/browser/renderer_host/b...
content/browser/renderer_host/browser_render_process_host.cc:570:
switches::kEnableCompositingForFixedPosition,
why is this here? i know we tend to cargo-cult it all the time but I can't
figure out what on earth it is for.

the way this flag works is it's checked in the browser process when building the
WebPreferences object for a given tab and then sent down via IPC. so why would
you want the switch to be on the renderer's command line?

[vangelis, 2011-10-27 06:33:04]

On 2011/10/27 06:19:52, jamesr wrote:
> lgtm
> 
>
http://codereview.chromium.org/8404026/diff/1/content/browser/renderer_host/b...
> File content/browser/renderer_host/browser_render_process_host.cc (right):
> 
>
http://codereview.chromium.org/8404026/diff/1/content/browser/renderer_host/b...
> content/browser/renderer_host/browser_render_process_host.cc:570:
> switches::kEnableCompositingForFixedPosition,
> why is this here? i know we tend to cargo-cult it all the time but I can't
> figure out what on earth it is for.
> 
> the way this flag works is it's checked in the browser process when building
the
> WebPreferences object for a given tab and then sent down via IPC. so why would
> you want the switch to be on the renderer's command line?

You're right. There's no reason to pass the flag down to the renderer.  Thanks!

[vangelis, 2011-10-28 23:19:39]

John, can I get an OWNERS ok too?  Thanks!

[jam, 2011-10-31 05:05:47]

lgtm