Fix memory corruption related to load blocking resource move

Fix memory corruption related to load blocking resource move

This fixes an issue where a resource loader belonging to one
ResourceFetcher was accidentally added as a blocking loader to another
ResourceFetcher, by checking the loader is part of the already
non-blocking loaders belonging to current ResourceFetcher.

This also adds DCHECKs on a couple of methods removing loaders from
hashmaps, to make sure we're not trying to remove a nullptr.

BUG=666563
Review-Url: https://codereview.chromium.org/2537303003
Cr-Commit-Position: refs/heads/master@{#435573}
(cherry picked from commit 7497990e6eb19dc8dd61de4f188553c9c054cef9)

Committed: https://chromium.googlesource.com/chromium/src/+/d63d800a8ab17eb1174bdbc8f13afa1ffb10193f

[Yoav Weiss, 2016-12-02 12:00:25]

Description was changed from

==========
Fix memory corruption related to load blocking resource move

This fixes an issue where a resource loader belonging to one
ResourceFetcher was accidentally added as a blocking loader to another
ResourceFetcher, by checking the loader is part of the already
non-blocking loaders belonging to current ResourceFetcher.

This also adds DCHECKs on a couple of methods removing loaders from
hashmaps, to make sure we're not trying to remove a nullptr.

BUG=666563

Review-Url: https://codereview.chromium.org/2537303003
Cr-Commit-Position: refs/heads/master@{#435573}
(cherry picked from commit 7497990e6eb19dc8dd61de4f188553c9c054cef9)
==========

to

==========
Fix memory corruption related to load blocking resource move

This fixes an issue where a resource loader belonging to one
ResourceFetcher was accidentally added as a blocking loader to another
ResourceFetcher, by checking the loader is part of the already
non-blocking loaders belonging to current ResourceFetcher.

This also adds DCHECKs on a couple of methods removing loaders from
hashmaps, to make sure we're not trying to remove a nullptr.

BUG=666563

Review-Url: https://codereview.chromium.org/2537303003
Cr-Commit-Position: refs/heads/master@{#435573}
(cherry picked from commit 7497990e6eb19dc8dd61de4f188553c9c054cef9)

Committed:
https://chromium.googlesource.com/chromium/src/+/d63d800a8ab17eb1174bdbc8f13a...
==========

[Yoav Weiss, 2016-12-02 12:00:32]

Committed patchset #1 (id:1) manually as
d63d800a8ab17eb1174bdbc8f13afa1ffb10193f.