[WebUI] Add a chrome://prefs-internals page

[WebUI] Add a chrome://prefs-internals page

Add a chrome://prefs-internals page that displays the JSON content of the
user's profile preferences and local state. This information is useful in
debugging when you need to know the state of a current preference.

Currently, this is particularly hard on ChromeOS, where you can't just
open the Preferences file in a text editor. This allows users to examine
preferences in the same way across platforms easily.

Add a simple page that displays this text-only information.

BUG=692853
Review-Url: https://codereview.chromium.org/2725903002
Cr-Commit-Position: refs/heads/master@{#458189}
Committed: https://chromium.googlesource.com/chromium/src/+/be084d2bff3da8eca87d2e68912712ebc995c56a

[Devlin, 2017-03-01 17:56:19]

Patchset #1 (id:1) has been deleted

[Devlin, 2017-03-01 17:58:16]

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

[commit-bot: I haz the power, 2017-03-01 17:58:36]

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

[Devlin, 2017-03-01 17:59:22]

rdevlin.cronin@chromium.org changed reviewers:
+ dbeam@chromium.org

[Devlin, 2017-03-01 17:59:23]

Getting around to this.  Dan, please take a look.  Also, let me know if you want
me to add a per-file rule to the OWNERS so that you're not stuck with this
forever (though I hope it's not much of a burden).

stevenjb@ FYI since he also wanted this.

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
File chrome/browser/profiles/profile_impl.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
chrome/browser/profiles/profile_impl.cc:512: content::URLDataSource::Add(this,
new PrefsInternalsSource(this));
Any better place for this?

[commit-bot: I haz the power, 2017-03-01 18:38:56]

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

[commit-bot: I haz the power, 2017-03-01 18:38:56]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[Dan Beam, 2017-03-08 18:40:59]

lgtm

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
File chrome/browser/profiles/profile_impl.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
chrome/browser/profiles/profile_impl.cc:512: content::URLDataSource::Add(this,
new PrefsInternalsSource(this));
On 2017/03/01 17:59:23, Devlin wrote:
> Any better place for this?

i don't really know but in an ideal world this wouldn't be instantiated until
the URL is requested, but it also doesn't seem to be very heavy

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
File chrome/browser/ui/webui/prefs_internals_browsertest.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
chrome/browser/ui/webui/prefs_internals_browsertest.cc:27: // implementation,
but we can at least assert that something is being shown.
why not just set a string pref to a very unique value and check for that value?

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
File chrome/browser/ui/webui/prefs_internals_source.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
chrome/browser/ui/webui/prefs_internals_source.cc:41:
callback.Run(base::RefCountedString::TakeString(&json));
it probably doesn't matter, but maybe do this in the blocking pool if it takes a
long time?

[Devlin, 2017-03-09 01:21:49]

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
File chrome/browser/profiles/profile_impl.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
chrome/browser/profiles/profile_impl.cc:512: content::URLDataSource::Add(this,
new PrefsInternalsSource(this));
On 2017/03/08 18:40:58, Dan Beam wrote:
> On 2017/03/01 17:59:23, Devlin wrote:
> > Any better place for this?
> 
> i don't really know but in an ideal world this wouldn't be instantiated until
> the URL is requested, but it also doesn't seem to be very heavy

Agreed - does the webui framework offer a way to do that for data sources?  (It
does for full-blown webui hosts, but I haven't seen a way to do it for this.)

[Dan Beam, 2017-03-09 02:16:54]

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
File chrome/browser/profiles/profile_impl.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/profiles...
chrome/browser/profiles/profile_impl.cc:512: content::URLDataSource::Add(this,
new PrefsInternalsSource(this));
On 2017/03/09 01:21:49, Devlin wrote:
> On 2017/03/08 18:40:58, Dan Beam wrote:
> > On 2017/03/01 17:59:23, Devlin wrote:
> > > Any better place for this?
> > 
> > i don't really know but in an ideal world this wouldn't be instantiated
until
> > the URL is requested, but it also doesn't seem to be very heavy
> 
> Agreed - does the webui framework offer a way to do that for data sources? 
(It
> does for full-blown webui hosts, but I haven't seen a way to do it for this.)

not really

[Devlin, 2017-03-20 16:51:34]

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

[commit-bot: I haz the power, 2017-03-20 16:52:00]

Dry run: 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, 2017-03-20 17:27:24]

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

[commit-bot: I haz the power, 2017-03-20 17:27:25]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Devlin, 2017-03-20 17:59:03]

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

[commit-bot: I haz the power, 2017-03-20 17:59:33]

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

[Devlin, 2017-03-20 19:08:31]

Patchset #3 (id:60001) has been deleted

[commit-bot: I haz the power, 2017-03-20 19:21:02]

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

[commit-bot: I haz the power, 2017-03-20 19:21:03]

Dry run: Try jobs failed on following builders:
  android_n5x_swarming_rel on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_n5x_...)

[Devlin, 2017-03-20 19:25:23]

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

[Devlin, 2017-03-20 19:25:31]

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
File chrome/browser/ui/webui/prefs_internals_browsertest.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
chrome/browser/ui/webui/prefs_internals_browsertest.cc:27: // implementation,
but we can at least assert that something is being shown.
On 2017/03/08 18:40:58, Dan Beam wrote:
> why not just set a string pref to a very unique value and check for that
value?

That's a good idea.  Done. (Very unique value == base::GenerateGUID())

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
File chrome/browser/ui/webui/prefs_internals_source.cc (right):

https://codereview.chromium.org/2725903002/diff/40001/chrome/browser/ui/webui...
chrome/browser/ui/webui/prefs_internals_source.cc:41:
callback.Run(base::RefCountedString::TakeString(&json));
On 2017/03/08 18:40:58, Dan Beam wrote:
> it probably doesn't matter, but maybe do this in the blocking pool if it takes
a
> long time?

Since this is user-blocking (the user tried to load the page) and prefs are
relatively small, I think it's probably fine to do it on this thread (since the
only part we can move to the blocking pool is writing the prefs out).  If you
insist, I can move it to a blocking pool, but I'm inclined to think that you're
right about it not mattering. :)

[commit-bot: I haz the power, 2017-03-20 19:25:41]

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

[Devlin, 2017-03-20 19:26:07]

rdevlin.cronin@chromium.org changed reviewers:
+ anthonyvd@chromium.org

[Devlin, 2017-03-20 19:26:08]

anthonyvd@, mind taking a look at profile_impl.cc?  (Feel free to recommend a
better place for this, if there is one. :))

[anthonyvd, 2017-03-20 19:31:43]

profile_impl.cc lgtm :)

[commit-bot: I haz the power, 2017-03-20 20:39:55]

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

[commit-bot: I haz the power, 2017-03-20 20:39:55]

Dry run: This issue passed the CQ dry run.

[Devlin, 2017-03-20 21:13:52]

The CQ bit was checked by rdevlin.cronin@chromium.org

[Devlin, 2017-03-20 21:13:53]

The patchset sent to the CQ was uploaded after l-g-t-m from dbeam@chromium.org
Link to the patchset: https://codereview.chromium.org/2725903002/#ps100001
(title: "Dan's")

[commit-bot: I haz the power, 2017-03-20 21:14:35]

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, 2017-03-20 21:22:27]

CQ is committing da patch.

Bot data: {"patchset_id": 100001, "attempt_start_ts": 1490044432976100,
"parent_rev": "47c0e8d177ffdb35e1e58650993200a1832e46f1", "commit_rev":
"be084d2bff3da8eca87d2e68912712ebc995c56a"}

[commit-bot: I haz the power, 2017-03-20 21:23:11]

Description was changed from

==========
[WebUI] Add a chrome://prefs-internals page

Add a chrome://prefs-internals page that displays the JSON content of the
user's profile preferences and local state. This information is useful in
debugging when you need to know the state of a current preference.

Currently, this is particularly hard on ChromeOS, where you can't just
open the Preferences file in a text editor. This allows users to examine
preferences in the same way across platforms easily.

Add a simple page that displays this text-only information.

BUG=692853
==========

to

==========
[WebUI] Add a chrome://prefs-internals page

Add a chrome://prefs-internals page that displays the JSON content of the
user's profile preferences and local state. This information is useful in
debugging when you need to know the state of a current preference.

Currently, this is particularly hard on ChromeOS, where you can't just
open the Preferences file in a text editor. This allows users to examine
preferences in the same way across platforms easily.

Add a simple page that displays this text-only information.

BUG=692853

Review-Url: https://codereview.chromium.org/2725903002
Cr-Commit-Position: refs/heads/master@{#458189}
Committed:
https://chromium.googlesource.com/chromium/src/+/be084d2bff3da8eca87d2e689127...
==========

[commit-bot: I haz the power, 2017-03-20 21:23:12]

Committed patchset #4 (id:100001) as
https://chromium.googlesource.com/chromium/src/+/be084d2bff3da8eca87d2e689127...

[gashohidul12, 2017-04-14 16:28:23]

On 2017/03/20 21:23:12, commit-bot: I haz the power wrote:
> Committed patchset #4 (id:100001) as
>
https://chromium.googlesource.com/chromium/src/+/be084d2bff3da8eca87d2e689127...