After r161087, the scale factor is being set directly in WebPageProxy, avoiding information duplication of the scale factor.
However, it takes a while to the scale factor gets applied in WebProcess and get back to UIProcess (WebPageProxy) due do IPC.
So, during this interval, if the user queries the contentScaleFactor to the WebView he will get the old scale factor.
This callback is useful to let the user know when it can rely on the contentScaleFactor. It is also important for API tests that might use contentScaleFactor
Created attachment 220058 [details]
Created attachment 220063 [details]
(In reply to comment #2)
> Created an attachment (id=220063) [details]
Forgot to fix the test
Created attachment 220263 [details]
*** This bug has been marked as a duplicate of bug 127090 ***