Fix StrictMode violation and add filter for scroll mode

Use one new thread to load the jar to fix StrictMode violation for
pre-rendering feature.
Besides, only send the hints if current mode is FLING_MODE for
pre-rendering feature. This can avoid fling optimization interruption
by SCROLL_MODE related operations.

Change-Id: I35296521f19fc6c0ba8ad91bb54f690a673e4fe2
CRs-Fixed: 2835362
2 files changed