Revert "mac: Allow Chrome to hand off its active URL to other devices."

Revert "mac: Allow Chrome to hand off its active URL to other devices."

This breaks Mac Memory tests. They're still building 32-bit, and this CL used
instance variables in a class extension, which is only supported in 64-bit
builds.

> This CL adds the class HandoffManager, which is responsible for interfacing
> with Apple's Handoff APIs. It takes a GURL, and exposes that GURL to Handoff.
>
> This CL adds the class ActiveWebContentsObserver, which is responsible for
> listening to changes to the active browser, the active tab, and the visible
> URL. It notifies its delegate when any of this state might have changed.
>
> AppControllerMac is the delegate of ActiveWebContentsObserver, as well as the
> owner of the HandoffManager. When it receives a delegate callback, it passes an
> updated GURL to the HandoffManager. There is some minimal logic in
> AppControllerMac that prevents URLs from incognito windows from being passed to
> the HandoffManager.
>
> BUG=431051, 438823
> Committed: https://crrev.com/708abc5b0abb5e0916d779bf6d1342fd472a2aa1
> Cr-Commit-Position: refs/heads/master@{#307846}

TBR=avi@chromium.org
NOTRY=true
BUG=431051, 438823
Committed: https://crrev.com/c429dd655de4317b2366440dd2c00ee4733136cf
Cr-Commit-Position: refs/heads/master@{#307947}

[erikchen, 2014-12-11 19:27:21]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2014-12-11 19:28:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/799583002/1

[commit-bot: I haz the power, 2014-12-11 19:30:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-11 19:31:11]

Patchset 1 (id:??) landed as
https://crrev.com/c429dd655de4317b2366440dd2c00ee4733136cf
Cr-Commit-Position: refs/heads/master@{#307947}