CDD: Relax requirements for WebView useragent.

Allow the "$(MODEL)" and "Build/$(BUILD)" tokens to be omitted from the
WebView useragent string, to match the current/future behaviour of
Chrome on Android. This is a minor improvement to privacy (reduces
fingerprinting) and security (removes information that may be useful for
targeting exploits).

Bug: 122453525
Change-Id: I8200e619e62a30f84b7c2ebf68f8fa0be47d95b8
1 file changed