Bug 1100192 - [Keyboard][Handwriting] Add words prediction feature
Revert "Bug 982839 - Write a test to protect against the regression seen in bug 981804 (navigate out of fullscreen video)" for f2 test failures

This reverts commit 801300deb395acf4a1a61c511a63969e3aac4c83.
Merge pull request #26269 from weideng/bug1100192

Bug 1100192 - [Keyboard][Handwriting] Add words prediction feature. r=timdream