Move SystemMonitor to base/.

Move SystemMonitor to base/.

I plan to use SystemMonitor in net/.

Fix up the Mac implementation not to use Cocoa APIs since @interface is not allowed in base.

BUG=none
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=85732

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=85737

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=85740

[willchan no longer on Chromium, 2011-05-12 07:39:31]

Hey Brett,

Here's the move. I have to figure out how to resolve some Mac issue with
@interface in base, but I'm bugging thakis@ for help on that. The rest of the
code should be ready for review.

[brettw, 2011-05-12 15:57:58]

LGTM

[willchan no longer on Chromium, 2011-05-14 17:41:06]

+avi

Turns out I had to gut the SystemMonitor implementation for OS X due to not
being allowed to use @interface in base. So I had to rewrite it using the C APIs
instead. Avi, you wrote the original implementation based on the Cocoa Obj-C
API. Can you take a look at my rewrite? It's based off the sample code provided
in http://developer.apple.com/library/mac/#qa/qa1340/_index.html.

[Avi (use Gerrit), 2011-05-18 04:07:32]

LGTM

[commit-bot: I haz the power, 2011-05-18 06:46:30]

Can't process patch for file base/system_monitor/system_monitor.cc.
A +