GN Incremental Install: Reinstall apk regardless of cached values

GN Incremental Install: Reinstall apk regardless of cached values

It sometimes happens that a dev will uninstall an app on device
manually. This currently breaks incremental installs, because the DeviceUtils
cache thinks the apk already exists.

To fix this, verify that cached apk paths actually exist the first time
a cached apk path value is used.

BUG=520082
Committed: https://crrev.com/164d0c34c518d359c00099597f92ca967d863708
Cr-Commit-Position: refs/heads/master@{#352774}

[agrieve, 2015-10-07 03:08:58]

agrieve@chromium.org changed reviewers:
+ jbudorick@chromium.org

[agrieve, 2015-10-07 03:13:15]

On 2015/10/07 03:08:58, agrieve wrote:
> mailto:agrieve@chromium.org changed reviewers:
> + mailto:jbudorick@chromium.org

ptal.

This actually came up because on my S5, my incrementally-installed app is
automatically uninstalled by some Knox service after a while!

Considered using timestamps (verify values that were not put in within the last
minute) but this feels a bit too heuristicy to me.
There are obviously other ways that the cache could become wrong (e.g. user adb
install -r), but I think the scripts will generally do the right thing in this
case anyways (md5 mismatch triggers maybe unnecessary re-install), and I want to
see if we hit any other problems before trying to add work-arounds for them.

[jbudorick, 2015-10-07 03:20:06]

lgtm

[agrieve, 2015-10-07 03:36:04]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-10-07 03:36:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1392813002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1392813002/20001

[commit-bot: I haz the power, 2015-10-07 05:12:55]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-07 05:13:44]

Patchset 2 (id:??) landed as
https://crrev.com/164d0c34c518d359c00099597f92ca967d863708
Cr-Commit-Position: refs/heads/master@{#352774}