Explicitly check for an installed WebAPK before starting installation

Explicitly check for an installed WebAPK before starting installation

This CL moves the checking for whether a WebAPK is already installed from
GooglePlayWebApkInstallDelegate to WebApkInstaller. This enables checking
whether the WebAPK is already installed only for installs and not updates.

Previously, the check was done for both installs and updates and prevented
updates from occurring.

BUG=699870
Review-Url: https://codereview.chromium.org/2739303005
Cr-Commit-Position: refs/heads/master@{#456436}
(cherry picked from commit 5ed6bd7f20513e2df40909ccd6e1935d3021fcb3)

Review-Url: https://codereview.chromium.org/2755723005 .
Cr-Commit-Position: refs/branch-heads/3029@{#245}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/aa962b931c34b789ce8193c2a616226ed221f48b

[pkotwicz, 2017-03-16 18:04:37]

Description was changed from

==========
Explicitly check for an installed WebAPK before starting installation

This CL moves the checking for whether a WebAPK is already installed from
GooglePlayWebApkInstallDelegate to WebApkInstaller. This enables checking
whether the WebAPK is already installed only for installs and not updates.

Previously, the check was done for both installs and updates and prevented
updates from occurring.

BUG=699870

Review-Url: https://codereview.chromium.org/2739303005
Cr-Commit-Position: refs/heads/master@{#456436}
(cherry picked from commit 5ed6bd7f20513e2df40909ccd6e1935d3021fcb3)
==========

to

==========
Explicitly check for an installed WebAPK before starting installation

This CL moves the checking for whether a WebAPK is already installed from
GooglePlayWebApkInstallDelegate to WebApkInstaller. This enables checking
whether the WebAPK is already installed only for installs and not updates.

Previously, the check was done for both installs and updates and prevented
updates from occurring.

BUG=699870

Review-Url: https://codereview.chromium.org/2739303005
Cr-Commit-Position: refs/heads/master@{#456436}
(cherry picked from commit 5ed6bd7f20513e2df40909ccd6e1935d3021fcb3)

Review-Url: https://codereview.chromium.org/2755723005 .
Cr-Commit-Position: refs/branch-heads/3029@{#245}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/aa962b931c34b789ce8193c2a616...
==========

[pkotwicz, 2017-03-16 18:04:39]

Committed patchset #1 (id:1) manually as
aa962b931c34b789ce8193c2a616226ed221f48b.