Revert of [Android:WebAPK] Don't add webapp to homescreen if WebAPK install times out part 2/3 (patchset #2 id:20001 of https://codereview.chromium.org/2728053002/ )

Reason for revert:
This is causing build failures on clang-clankium-tot-builder
See:
https://crbug.com/702086
https://uberchromegw.corp.google.com/i/internal.client.clank_tot/builders/clang-clankium-tot-builder/builds/43251

Original issue's description:
> [Android:WebAPK] Don't add webapp to homescreen if WebAPK install times out part 2/3
>
> This CL:
> - Changes GooglePlayWebApkInstallDelegate#installAsync() to return a
>   WebApkInstallResult in the callback.
> - Deletes unused GooglePlayWebApkInstallDelegate#canInstallWebApk().
>
> BUG=696132
>
> Review-Url: https://codereview.chromium.org/2728053002
> Cr-Commit-Position: refs/heads/master@{#457300}
> Committed: https://chromium.googlesource.com/chromium/src/+/19d929ae378491116d7683764baa6365d1ddd50d

TBR=dominickn@chromium.org,pkotwicz@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=696132

Review-Url: https://codereview.chromium.org/2757563002
Cr-Commit-Position: refs/heads/master@{#457361}
2 files changed