[Remoting Android] Move pairing secret fetcher to the network thread

JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc: https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc_Q/edit?usp=sharing

BUG=614242
Committed: https://crrev.com/8d06c0ca4c2784ac15f480bba74956bad5cbe522
Cr-Commit-Position: refs/heads/master@{#398364}

[Yuwei, 2016-06-07 00:53:00]

yuweih@chromium.org changed reviewers:
+ lambroslambrou@chromium.org

[Yuwei, 2016-06-07 00:53:01]

ptal

[Lambros, 2016-06-07 01:21:12]

lgtm

Fix phrasing of the CL summary line. Maybe:
Move pairing secret fetcher to the network thread.

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_cli...
File remoting/client/jni/jni_client.cc (right):

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_cli...
remoting/client/jni/jni_client.cc:70: secret_fetcher_.release());
Indentation looks wrong here (and also on line 66). git cl format?

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
File remoting/client/jni/jni_pairing_secret_fetcher.h (right):

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:18: // on the network thread.
Actually, it's created on the UI thread, but thereafter used on the network
thread.

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:37:
base::WeakPtr<JniPairingSecretFetcher> GetWeakPtr();
Can this be removed?

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:40: static void
FetchSecretOnUI(base::WeakPtr<JniClient> client,
rename: FetchSecretOnUiThread

[Yuwei, 2016-06-07 17:16:15]

Description was changed from

==========
[Remoting Android] Make pairing secret fetcher network thread class

JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

to

==========
[Remoting Android] Make pairing secret fetcher network thread class

JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

[Yuwei, 2016-06-07 17:16:29]

Description was changed from

==========
[Remoting Android] Make pairing secret fetcher network thread class

JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

to

==========
JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

[Yuwei, 2016-06-07 17:36:00]

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
File remoting/client/jni/jni_pairing_secret_fetcher.h (right):

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:37:
base::WeakPtr<JniPairingSecretFetcher> GetWeakPtr();
On 2016/06/07 01:21:12, Lambros wrote:
> Can this be removed?

Currently JniClient passes in a WeakPtr of the secret fetcher to the
JniInstance. We can make that pointer a raw pointer since secret_fetcher_ will
always be deleted after JniInstance is deleted. I personally prefer WeakPtr
since we don't need to care too much about the deletion order... WDYT?

[Yuwei, 2016-06-07 17:44:26]

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
File remoting/client/jni/jni_pairing_secret_fetcher.h (right):

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:37:
base::WeakPtr<JniPairingSecretFetcher> GetWeakPtr();
On 2016/06/07 01:21:12, Lambros wrote:
> Can this be removed?

Hmm... Just thought about this again... The ctor of JniInstance is doing
something like:

client_auth_config_.fetch_secret_callback =
base::Bind(&JniPairingSecretFetcher::FetchSecret, secret_fetcher);

Looks like secret_fetcher.FetchSecret() will be run on the network thread at
some point... I think it's safer to use WeakPtr in this case...

[Yuwei, 2016-06-07 18:00:55]

The CQ bit was checked by yuweih@chromium.org

[Yuwei, 2016-06-07 18:00:56]

The patchset sent to the CQ was uploaded after l-g-t-m from
lambroslambrou@chromium.org
Link to the patchset: https://codereview.chromium.org/2047613002/#ps20001
(title: "Reviewer's Feedback")

[Yuwei, 2016-06-07 18:01:03]

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_cli...
File remoting/client/jni/jni_client.cc (right):

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_cli...
remoting/client/jni/jni_client.cc:70: secret_fetcher_.release());
On 2016/06/07 01:21:12, Lambros wrote:
> Indentation looks wrong here (and also on line 66). git cl format?

Done.

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
File remoting/client/jni/jni_pairing_secret_fetcher.h (right):

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:18: // on the network thread.
On 2016/06/07 01:21:12, Lambros wrote:
> Actually, it's created on the UI thread, but thereafter used on the network
> thread.

Done. Fixed comments.

https://codereview.chromium.org/2047613002/diff/1/remoting/client/jni/jni_pai...
remoting/client/jni/jni_pairing_secret_fetcher.h:40: static void
FetchSecretOnUI(base::WeakPtr<JniClient> client,
On 2016/06/07 01:21:12, Lambros wrote:
> rename: FetchSecretOnUiThread

Done.

[commit-bot: I haz the power, 2016-06-07 18:02:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2047613002/20001

[commit-bot: I haz the power, 2016-06-07 19:10:29]

Description was changed from

==========
JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

to

==========
JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

[commit-bot: I haz the power, 2016-06-07 19:10:30]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-07 19:13:44]

Description was changed from

==========
JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242
==========

to

==========
JniPairingSecretFetcher currently runs on the UI thread but the secret
fetching callback will be run on the network thread. Per wez@'s suggestion
it will be more straightforward if the class runs on network thread and
post task to UI thread to fetch the secret.

Doc:
https://docs.google.com/document/d/1ZK-UQSC_rTjNsBa_MFbCmCh3fQRPFuVAwKhWnTZqc...

BUG=614242

Committed: https://crrev.com/8d06c0ca4c2784ac15f480bba74956bad5cbe522
Cr-Commit-Position: refs/heads/master@{#398364}
==========

[commit-bot: I haz the power, 2016-06-07 19:13:44]

Patchset 2 (id:??) landed as
https://crrev.com/8d06c0ca4c2784ac15f480bba74956bad5cbe522
Cr-Commit-Position: refs/heads/master@{#398364}