Set a more usable default font size

[Rosuav]

Description

Set a default font size of 16px to ensure that text is readable when unstyled.

Motivation and Context

The default font size in most browsers is 16px, but the default here appears sometimes to be 1px. This results in unreadable text (see eg the confusion in #226 which ultimately was caused by this), and is inconsistent.

How Has This Been Tested?

Fired up several pages. Browser plugin was built against CEF 75.1.14+gc81164e+chromium-75.0.3770.100 - didn't test with other CEF versions. It might be that this patch only benefits older browser builds, but that's still worthwhile as 3770 is the one named in the OBS installation instructions.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.

[WizardCM]

In testing, this is exclusive to 3770 and only on Linux as far as we could tell. Is it common for apps using CEF to manually set the font size?

[Rosuav]

I'm not saying the bug is exclusive to 3770/Linux - just that that's all I have access to test it on. I'm currently trying to build other CEFs for testing, but that's its own job and may or may not succeed.

[Rosuav]

No idea how common it is for apps to manually set the font size, but given that I'm setting it to the most commonly-used default, it's going to do nothing if it wasn't a problem.

[WizardCM]

No I know, I mean when we were preparing 25.x builds with the browser source, we ran into the same issue, and the reason we ended up jumping to 3809 on our official build on Linux is because the issue didn't occur there. We originally thought it was a rendering bug, but turned out to be font-size related.

Personally I think this change is fine if other browsers also use it as default, as long as we can verify that.

[Rosuav]

Actually, can confirm that this does not happen on 3809, so this is a fix to ensure that the version listed in the installation instructions does work. Alternatively, changing the installation instructions (and including a fully-built CEF for download) would resolve this issue.

[aerogus]

Great idea this default font size. It may resolve the bug I have with "em" or "rem" units in my CSS. I had to switch to "px" units.

[Rosuav]

Yes, it should resolve that (based on my testing).