[android_webview] Save boundary interfaces from proguard obfuscation
am: 68349a8634

Change-Id: I2042a403bf1ddf7492e3f07134953dc76ece634a
tree: 31c183ac4bc237e034b2d4fe13cf68f410d27aaa
  1. src/
  2. BUILD.gn
  3. DEPS
  4. proguard.flags