Google says the challenge in bringing this feature to mobile is how to ensure reporting and analyzing potentially harmful while not using a ton of data, which can be a precious commodity.
To accomplish this Google says the riskiest sites are reported first. Also, certain types of attacks, like social engineering and phishing, are targeted in regions where they have a track record of popping up.
To ensure you have Safe Browsing Mode enabled, open Chrome and head to Settings > Privacy.
From here you can enable or disable Safe Browsing, along with a number of other features.
Why this matters: Google has a high interest in keeping web browsing safe given Chrome’s large marketshare and the company’s advertising platform. In general it’s a good idea to keep Safe Browsing mode on, as attackers continue to grow ever more sophisticated with their capabilities.