Cherry pick [android_webview] Don't unconditionally add pak files to system image.

Cherry pick of
https://src.chromium.org/viewvc/chrome?view=rev&revision=285893

[android_webview] Don't unconditionally add pak files to system image.

The make rules we have make it impossible to not include the
android_webview pak files in the system image.

BUG=396741
R=primiano@chromium.org

Committed:
https://src.chromium.org/viewvc/chrome?view=rev&revision=285893

Bug: 16723226
Change-Id: I02995b603cb018a496b18787c7a5c497aac4fd74
2 files changed