Make WebViewLibraryLoader interface more flexible.

Pass the library file name to WebViewLibraryLoader.loadNativeLibrary
instead of passing the ApplicationInfo, which was only used to look the
native library file name up. This will allow loadNativeLibrary to be
called from the webview zygote, which doesn't have the ApplicationInfo
available.

Bug: 63749735
Test: CtsWebkitTests
Change-Id: I0bd2de38cd1a0112bbeee6225563d4d0add048e7