mediaview: Hack to avoid Files app to freeze soon after login.

mediaview: Hack to avoid Files app to freeze soon after login.

Files app freezes until storage::WatcherManager::AddWatcher() finishes.
To avoid this issue, add a hack to ArcDocumentsProviderRoot so that
AddWatcher() pretends to finish immediately.

Ideally this issue should be fixed in Files app. However its current
design assumes operations on changing the current working directory
are serialized. Therefore this change tries to workaround the issue in
a quick way.

BUG=chromium:698624
TEST=Files app does not freeze soon after login.
TEST=unit_tests

Review-Url: https://codereview.chromium.org/2726373002
Cr-Commit-Position: refs/heads/master@{#456945}
(cherry picked from commit 3f89cb4d2e652514501cd26bcf7fd75f1fda73f8)

Review-Url: https://codereview.chromium.org/2753743005 .
Cr-Commit-Position: refs/branch-heads/3029@{#227}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/7f1b243d17654d56433da28ad4d4e8865f7a3046

[Shuhei Takahashi, 2017-03-16 06:08:07]

Description was changed from

==========
mediaview: Hack to avoid Files app to freeze soon after login.

Files app freezes until storage::WatcherManager::AddWatcher() finishes.
To avoid this issue, add a hack to ArcDocumentsProviderRoot so that
AddWatcher() pretends to finish immediately.

Ideally this issue should be fixed in Files app. However its current
design assumes operations on changing the current working directory
are serialized. Therefore this change tries to workaround the issue in
a quick way.

BUG=chromium:698624
TEST=Files app does not freeze soon after login.
TEST=unit_tests

Review-Url: https://codereview.chromium.org/2726373002
Cr-Commit-Position: refs/heads/master@{#456945}
(cherry picked from commit 3f89cb4d2e652514501cd26bcf7fd75f1fda73f8)
==========

to

==========
mediaview: Hack to avoid Files app to freeze soon after login.

Files app freezes until storage::WatcherManager::AddWatcher() finishes.
To avoid this issue, add a hack to ArcDocumentsProviderRoot so that
AddWatcher() pretends to finish immediately.

Ideally this issue should be fixed in Files app. However its current
design assumes operations on changing the current working directory
are serialized. Therefore this change tries to workaround the issue in
a quick way.

BUG=chromium:698624
TEST=Files app does not freeze soon after login.
TEST=unit_tests

Review-Url: https://codereview.chromium.org/2726373002
Cr-Commit-Position: refs/heads/master@{#456945}
(cherry picked from commit 3f89cb4d2e652514501cd26bcf7fd75f1fda73f8)

Review-Url: https://codereview.chromium.org/2753743005 .
Cr-Commit-Position: refs/branch-heads/3029@{#227}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/7f1b243d17654d56433da28ad4d4...
==========

[Shuhei Takahashi, 2017-03-16 06:08:10]

Committed patchset #1 (id:1) manually as
7f1b243d17654d56433da28ad4d4e8865f7a3046.