Upstream: DexOptimizer and DexLoader classes

This CL upstreams DexOptimizer and DexLoader
DexOptimizer extracts a .dex file from an APK
DexLoader creates a ClassLoader from the extracted .dex file

BUG=609122
R=hanxi
TBR=yfriedman (TBR for new DEPS in chrome/android/webapk/shell_apk/javatests)

Review-Url: https://codereview.chromium.org/1981473002
Cr-Commit-Position: refs/heads/master@{#394656}
15 files changed