desktop-pwas: Replace WebConstants LaunchContainer with DisplayMode

ExternalInstallOptions and InstallManager::InstallParams now contain
DisplayMode instead of LaunchContainer.

This allows minimal-ui to be supported by InstallManager.

TBR=jonmann@chromium.org

Bug: 1009909
Change-Id: I13adaf8f834f2cb2d8e80d7ad3bffc24b9d9d73d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1849471
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Alexey Baskakov <loyso@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704545}
21 files changed