Revert "Files app: Select My files when there are no volumes"

This reverts commit 5cd8c123e452c0b76fbbcaf53e82d86ca7d54930.

Reason for revert:

Findit ( identified CL at revision 599026 as the
culprit for flakes in the build cycles as shown on:

Sample Failed Build:

Sample Failed Step: viz_browser_tests

Sample Flaky Test: FileDisplay/FilesAppBrowserTest.Test/fileDisplayWithoutVolumesThenMountDrive_DriveFs

Original change's description:
> Files app: Select My files when there are no volumes
> Make Files app select "My files" when there are no available volumes,
> this to allow Files app to behave properly when volumes subsequently
> become available.
> Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
> non-null |displayRoot| before trying to change to |displayRoot|. This
> fixes the error "Cannot read property 'getParent' of null" when Drive
> volume becomes available before Downloads volume, which is the default
> volume/root.
> Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
> DriveFsTestVolume can re-mount itself.
> Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
> Bug: 893161, 884967
> Change-Id: Ic813b25261530495c11c9f641a92f6e07f883702
> Reviewed-on:
> Reviewed-by: Noel Gordon <>
> Reviewed-by: Sam McNally <>
> Commit-Queue: Luciano Pacheco <>
> Cr-Commit-Position: refs/heads/master@{#599026}

Change-Id: I883485c8fc1bdcc22dba93cc4b03b7c157dcb5f2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 893161, 884967, 889703
Cr-Commit-Position: refs/heads/master@{#599190}
6 files changed