GitLab

This patch:
- Moved files from native to broswer mechanically by
using tools/git/move_source_file.py.

- Moved content in //android_webview/native/BUILD.gn to
//android_webview/BUILD.gn.

- Updated //android_webview/test/BUILD.gn for unit tests in
//android_webview/native/.

- Updated corresponding include_rules to //android_webview/broswer/DEPS.

- Contains a lot of formatting from git cl format.

BUG=716604
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2863233002
Cr-Commit-Position: refs/heads/master@{#470203}