[Devtools] Fixed bug with NetworkLog depending on ResourceTreeModel

[Devtools] Fixed bug with NetworkLog depending on ResourceTreeModel

ResourceTreeModel is currently required by NetworkLog and causes a crash
when a NetworkRequest tries to access it's NetworkLog because it does not
exist. This bug fixes this dependency.

R=dgozman,caseq
BUG=668032

[allada, 2016-12-01 23:16:42]

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

[commit-bot: I haz the power, 2016-12-01 23:17:07]

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

[allada, 2016-12-01 23:17:23]

PTL... I was going to write a test for this, but because it happens mostly for
service workers and service workers requires HTTPS and bots have limited support
for LayoutTests as HTTPS it's going to be a lot of work.

[commit-bot: I haz the power, 2016-12-02 00:59:25]

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

[commit-bot: I haz the power, 2016-12-02 00:59:27]

Dry run: This issue passed the CQ dry run.

[dgozman, 2016-12-02 18:08:22]

Let's instead move page-load functionality to ResourceTreeModel?

Re: https in tests. localhost is considered to be a secure location, so http
LayoutTests perfectly work with serviceworkers.

[pfeldman, 2016-12-02 19:48:28]

When/why do we have network log and not have resource tree model?

[allada, 2016-12-03 02:28:34]

On 2016/12/02 19:48:28, pfeldman wrote:
> When/why do we have network log and not have resource tree model?

Because we end up having requests that are not apart of a NetworkLog.

see:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/devtools/front...

here we are explicitly expecting it to be present:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/devtools/front...

We should always have a NetworkLog for requests, but requests may not be tied to
a ResourceTreeModel, since it may have been loaded from another target like
service worker which does have network capability but does not have a dom.
(also: node does not have a ResourceTreeModel and currently not network either).

[dgozman, 2017-07-15 05:41:12]

Should we close this?