Fixes and tweaks

[croqaz]

This PR is a short continuation of #770 , to add 2 log messages.
Also fix a non-obvious error, when cssText = getCssRulesString(...) crashes because stylesheet=null and snapshot function doesn't return. It happens sometimes: #764 (comment)
Also removed CSSStyleSheet.rules which is deprecated: https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleSheet#legacy_properties

[croqaz]

Hi @Mark-Fenng ! Thanks for taking a look at the PR.
I noticed you fixed some issues with the inline image, but there's a try catch that I think can be improved a bit, so I hope you don't mind I moved it into the new function recordInlineImage that you have created: 4089127
I believe it doesn't make sense to try catch the function definition, so it should be merged.

Feel free to suggest any changes, I'm open :)

[YunFeng0817]

@croqaz Thanks for your contribution. You may still have two little points to correct and finally, don't forget to rebase the latest master branch coz there are conflicts between them.

[croqaz]

Thank you for all the guidance @Mark-Fenng !