Use base::ScopedTypeRef for CGL types

Use base::ScopedTypeRef for CGL types.

Use gfx::ScopedCGLSetCurrentContext for setting the current
context in the browser process. When calling CGLSetCurrentContext,
the pre-existing code inconsitently did either of restoring the
context, setting the context to NULL, or leaving the context set.
This makes the behavior consistent. It also makes error checking
pervasive.

BUG=245900
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=250399

[ccameron, 2014-02-07 01:11:29]

For illustration (though if discussion on the other topic has no controversy,
then review as well).

https://codereview.chromium.org/147493011/diff/1/content/browser/renderer_hos...
File content/browser/renderer_host/compositing_iosurface_layer_mac.mm (right):

https://codereview.chromium.org/147493011/diff/1/content/browser/renderer_hos...
content/browser/renderer_host/compositing_iosurface_layer_mac.mm:111: // a way
to avoid doing this.
Note that this isn't anything new with this patch  -- just documentation and
robust-ifying the existing scheme. This scheme is part of the way CAOpenGLLayer
does drawing (which is also how non-CA paths do this). I'd like to change this
to a way that we don't pause in the drawing code, but rather delay the actual
resizes.

[ccameron, 2014-02-07 07:17:24]

Given that it looks like there's consensus on base::ScopedTypeRef, this is ready
for review as well.

https://codereview.chromium.org/147493011/diff/50001/content/browser/renderer...
File content/browser/renderer_host/compositing_iosurface_layer_mac.mm (right):

https://codereview.chromium.org/147493011/diff/50001/content/browser/renderer...
content/browser/renderer_host/compositing_iosurface_layer_mac.mm:104: if
(cached_view->render_widget_host_) {
Hopefully this comment clears up some of the terror regarding this function. I'm
going to try moving this block around in future changes, to see if I can avoid
the nested run loop in this callback (but, in the future).

[Ken Russell (switch to Gerrit), 2014-02-10 19:32:23]

Looks like a good cleanup.

LGTM once this compiles, has been tested locally, and runs cleanly on the GPU
bots.

[ccameron, 2014-02-10 19:57:55]

Thanks!

(looks like my tryjob didn't pick up the prereq change)

[ccameron, 2014-02-10 19:57:56]

Thanks!

(looks like my tryjob didn't pick up the prereq change)

[ccameron, 2014-02-11 06:20:06]

The CQ bit was checked by ccameron@chromium.org

[commit-bot: I haz the power, 2014-02-11 06:20:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ccameron@chromium.org/147493011/150001

[commit-bot: I haz the power, 2014-02-11 14:24:43]

Change committed as 250399