Extract TabModelObservers from tab_model.mm to its own file.

Extract TabModelObservers from tab_model.mm to its own file.

TabModelObservers is a helper class that allow for forwarding
TabModelObserver events to multiple TabModelObserver instances.
Extract it to a separate file in preparation of refactoring the
TabModel.

BUG=687207
Review-Url: https://codereview.chromium.org/2684073002
Cr-Commit-Position: refs/heads/master@{#450320}
Committed: https://chromium.googlesource.com/chromium/src/+/0a762e43411be0bd7426da0d749b7e49d4de47b3

[sdefresne, 2017-02-08 15:37:36]

The CQ bit was checked by sdefresne@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-02-08 15:37:57]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[sdefresne, 2017-02-08 15:37:59]

sdefresne@chromium.org changed reviewers:
+ rohitrao@chromium.org

[sdefresne, 2017-02-08 15:38:00]

Please take a look.

[commit-bot: I haz the power, 2017-02-08 16:46:54]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-02-08 16:46:55]

Dry run: This issue passed the CQ dry run.

[sdefresne, 2017-02-13 15:45:05]

rohitrao: ping

[rohitrao (ping after 24h), 2017-02-13 19:24:28]

lgtm

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
File ios/chrome/browser/tabs/tab_model.mm (right):

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
ios/chrome/browser/tabs/tab_model.mm:253:
observersWithProtocol:@protocol(TabModelObserver)] retain]);
Could you instead use the new +[TabModelObservers observers] method?

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
File ios/chrome/browser/tabs/tab_model_observers.mm (right):

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
ios/chrome/browser/tabs/tab_model_observers.mm:13: + (instancetype)observers {
Was this not necessary in the original implementation?  Why have you added it
now?

[sdefresne, 2017-02-14 10:11:31]

Thank you for the review.

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
File ios/chrome/browser/tabs/tab_model.mm (right):

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
ios/chrome/browser/tabs/tab_model.mm:253:
observersWithProtocol:@protocol(TabModelObserver)] retain]);
On 2017/02/13 19:24:28, rohitrao wrote:
> Could you instead use the new +[TabModelObservers observers] method?

Oh, yeah this is why I added the +observers method. Thank you for catching this.

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
File ios/chrome/browser/tabs/tab_model_observers.mm (right):

https://codereview.chromium.org/2684073002/diff/1/ios/chrome/browser/tabs/tab...
ios/chrome/browser/tabs/tab_model_observers.mm:13: + (instancetype)observers {
On 2017/02/13 19:24:28, rohitrao wrote:
> Was this not necessary in the original implementation?  Why have you added it
> now?

This is just a convenience method, not necessary but allow for shorter lines by
replacing:

  TabModelObserver* observers = [TabModelObservers
      observersWithProtocol:@protocol(TabModelObserver)];

with:

  TabModelObserver* observers = [TabModelObservers observers];

[sdefresne, 2017-02-14 10:12:15]

The CQ bit was checked by sdefresne@chromium.org

[sdefresne, 2017-02-14 10:12:15]

The patchset sent to the CQ was uploaded after l-g-t-m from
rohitrao@chromium.org
Link to the patchset: https://codereview.chromium.org/2684073002/#ps20001
(title: "Rebase and address comment.")

[commit-bot: I haz the power, 2017-02-14 10:12:40]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-14 11:11:29]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1487067135659790,
"parent_rev": "226674d91af605cbac623ef70b4a5a74edb65978", "commit_rev":
"0a762e43411be0bd7426da0d749b7e49d4de47b3"}

[commit-bot: I haz the power, 2017-02-14 11:12:11]

Description was changed from

==========
Extract TabModelObservers from tab_model.mm to its own file.

TabModelObservers is a helper class that allow for forwarding
TabModelObserver events to multiple TabModelObserver instances.
Extract it to a separate file in preparation of refactoring the
TabModel.

BUG=687207
==========

to

==========
Extract TabModelObservers from tab_model.mm to its own file.

TabModelObservers is a helper class that allow for forwarding
TabModelObserver events to multiple TabModelObserver instances.
Extract it to a separate file in preparation of refactoring the
TabModel.

BUG=687207

Review-Url: https://codereview.chromium.org/2684073002
Cr-Commit-Position: refs/heads/master@{#450320}
Committed:
https://chromium.googlesource.com/chromium/src/+/0a762e43411be0bd7426da0d749b...
==========

[commit-bot: I haz the power, 2017-02-14 11:12:12]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/0a762e43411be0bd7426da0d749b...