See also: http://crrev/i/611093.

WebView startup is currently unnecessarily delayed by querying for Safe Browsing user consent. We query for Safe Browsing user consent asynchronously using PlatformServiceBridge#querySafeBrowsingUserConsent [1].

Under the hood, the downstream implementation of this method calls an async GMS API [2]. Even though that API itself is async, the synchronous parts of the method take a long time (initial estimates are ~9ms, thorough results will be posted here [3]).

We should post this work (similar to http://crrev/i/611093) to improve startup.

Because querySafeBrowsingUserConsent is asynchronous, it has always been possible that we would detect a known-malicious URL, but would not know the user's opt-in preference (and would therefore mark this as a "safe" URL). If we re-implement querySafeBrowsingUserConsent to use AsyncTask, we should be careful to check that we don't hit this case significantly more frequently.

[1] https://cs.chromium.org/chromium/src/android_webview/java/src/org/chromium/android_webview/PlatformServiceBridge.java?l=54&rcl=90e886d1638437a1346367e36bbff675a826fe66
[2] https://cs.corp.google.com/clankium/src/clank/android_webview/java/src/org/chromium/android_webview/PlatformServiceBridgeImpl.java?q=package:clankium+f:clank+querySafeBrowsingUserConsent&l=136
[3] https://docs.google.com/spreadsheets/d/1r-u4la0eXvaTIwsuoSO5jBmghn2TBBR9Dj8FGtyvSqg/edit?usp=sharing