The left screenshot shows the result obtained from Google's online spell checker: "Gmail" is the most likely spelling correction for "Gmal", but a dictionary-based approach can't tell you that. Google can:
"Google Chrome can provide smarter spell-checking by sending what you type in the browser to Google servers, allowing you to use the same spell-checking technology used by Google search," explains Google.
It's disappointing to see that the most useful suggestion is added after all the other suggestions, which are terrible. After all, Google's search engine has probably the best spell checker and Chrome only uses it to supplement the list of suggestions that's generated locally. The latency makes it difficult to instantly display the suggestions obtained from a web service, but Google should find a way to minimize the delay and switch to the online spell checker.
Right now, the feature is disabled by default, but you can enable it by right-clicking on a text box, mousing over "Spell-checking options" and clicking "Ask Google for suggestions". The feature can also be enabled from the settings page in Chrome Canary: just go to the "Under the hood" tab and check "Use a web service to help resolve spelling errors". This only works in the latest Canary/Dev Channel builds and in Chromium.