Harden against transiently unavailable backup transports

The init & clear operations are particularly important to ensure
delivery when at all possible, so we retry those periodically
if the transport is unavailable when we first attempt them.

Bug 11716868

Change-Id: I4860fe3d4e99618b2cd194c83162bd7cbd5a83a9
DO NOT MERGE - Don't hang installs if the transport disappears

Bug 12991308

Cherry-pick from master.

Change-Id: Id1abedd77be7207e67d7ca11591973d33125459c
Add EventLog event for logging of attempts to call java.lang.Object.getClass

Bug: 13694467
Change-Id: I886c6ffb3a008d0cf701c1adc16c607cbf7dce39
Revert "WebView: Use chromium unless explicitly set to classic"

This reverts commit 2245c5f2ba9d9ed916e244f1c6a92f892ec3ee75.
Revert "Allow using Classic WebView"

This reverts commit 762df352ef23599854db4c29a1d380918424ba48.