[GENERIC viewer] Fix the background color of the findInput when the search term is not found

When a search term isn't found, the background color of the findInput is supposed to change (to red). This is currently not working as intended, because the CSS rule is not being applied correctly. (It seems that this broke in PR 2208.)

This patch also changes the background color to match the one used in the native Firefox findbar, since the old color seemed a bit too pink.
Prevent a "TypeError: pdfViewer is null" when the viewer loads (PR 5413 followup)

Currently if you manage to e.g. open the console (with <kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>K</kbd>) before the viewer is initialized, the following will be printed in the console: `TypeError: pdfViewer is null`.
This doesn't cause any actual errors, but nevertheless it seems like something we should avoid.

Followup to PR 5413.
Fixes typo in webgl.js
Merge pull request #5492 from jsundn/master

Fixes typo in webgl.js
Merge pull request #5488 from Snuffleupagus/presentationMode-no-zoom-followup

Prevent a "TypeError: pdfViewer is null" when the viewer loads (PR 5413 followup)
Merge pull request #5465 from Snuffleupagus/findbar-notFound-color

[GENERIC viewer] Fix the background color of the findInput when the search term is not found
fix passing null as Promise's onFullfilled (which is broken in Chrome 32)
Fallback to the |Dummy| Pattern when we fail to parse a Shading Pattern (issue 5509)
removed rounding of values in composeSMaskLuminosity

maskData comes out of maskCtx.getImageData, so is 0..255 clamped, and
the used multiplications will not create fractions needing rounding,
neither would addition.
increase chunk size in SMask composition to 1M pixels
Merge pull request #5516 from Snuffleupagus/issue-5509

Fallback to the |Dummy| Pattern when we fail to parse a Shading Pattern (issue 5509)
Merge pull request #5507 from palkan/fix-promise-null

Fix passing null as onFullfilled (which is broken in Chrome(-ium) 32)
Merge pull request #5523 from CodingFabian/remove-canvas-rounding-luminosity

removed rounding of values in composeSMaskLuminosity
Merge pull request #5524 from fkaelberer/increaseSMaskChunkSizeTo1M

Increases chunk size in SMask composition to 1M pixels