Revert "[Extensions] Remove manifest v1 support for accessible resources"

This reverts commit 7a1b3bb0f7aa68093639da976f3b4ecedd4585d8.

Reason for revert: Seems to have caused memory failures. Sample failure:
https://ci.chromium.org/buildbot/chromium.memory/Linux%20MSan%20Tests/8760
with this in the stack
views::WidgetDelegate::GetAccessibleWindowTitle

Original change's description:
> [Extensions] Remove manifest v1 support for accessible resources
> 
> In manifest version 1, all extension resources were considered
> accessible by the web (i.e., could be embedded within or
> requested by a web page). In manifest v2, only resources
> explicitly specified in the web_accessible_resources key are
> accessible. Remove support for manifest v1, and always check
> the web accessible resources.
> 
> Update unit tests to migrate relevant tests and remove tests for
> manifest v1-specific behavior.
> 
> Bug: 816677, 816679
> Change-Id: Id0dd3ef75cd5d49e3f87e45ac3a8b19a00391146
> Reviewed-on: https://chromium-review.googlesource.com/953177
> Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
> Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#545898}

TBR=rdevlin.cronin@chromium.org,karandeepb@chromium.org

Change-Id: Ifae57fc0f5cb2b738d48527af5e20c19eac5b0a9
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 816677, 816679
Reviewed-on: https://chromium-review.googlesource.com/981336
Reviewed-by: Ben Wells <benwells@chromium.org>
Commit-Queue: Ben Wells <benwells@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546010}
12 files changed