bug(linux): Keyman doesn't work with Chromium installed as Snap package

[ermshiperete]

With #11535 Chrome/Chromium works when installed as flatpak package, but not when installed as snap package.

[ermshiperete]

Test Matrix

Here's a test matrix of the current status, tested on Ubuntu 24.10 Oracular with #11535 applied.

Three versions of Chrome/Chromium installed:

• Snap (snap install chromium; start with /snap/bin/chromium)
• Flatpak (flatpak install flathub com.google.Chrome; start with flatpak run com.google.Chrome)
• Deb (Download from https://www.google.com/chrome/ and install with sudo apt install ./Downloads/google-chrome-stable_current_amd64.deb; start with google-chrome)

Tested on https://keyman.com/keyboards with the following cases:

• TEST_CHROME_IPA: Switch to "IPA (SIL)" keyboard. Type n>. Verify that the result is "ŋ".
• TEST_CHROME_KO: Switch to "Korean KORDA Jamo (SIL)" keyboard. Type han<space>geul<space>. Verify that the result is "한글".
• TEST_CHROME_HI: Switch to "Vedic Sanskrit Devanagari Phonetic (ITRANS)" keyboard. Type shrI. Verify that the result is "श्री".
• TEST_CHROME_KM: Switch to "Khmer Angkor" keyboard. Type xEjmr. Verify that the output is "ខ្មែរ".
• TEST_CHROME_KM_BS: With the output "ខ្មែរ" still being displayed, press Backspace key 5 times. Verify that after each keystroke a part of the string is removed and after the 5th backspace the entire word is deleted.

Result

	Snap	Flatpak	Deb
Wayland	❌	✅(1)	✅
X11	❌	✅(1)	✅

(1) TEST_CHROME_HI didn't display correctly, likely the correct font is not available in the flatpak. Copying and pasting in Writer showed that Keyman did produce the correct output.

[ermshiperete]

See also #7218