In old versions of the viewer, anchor links were used to be able to scroll a page into view. Since we for quite some time have had a `scrollIntoView` function which handles this, the anchor links are no longer necessary and I believe that they can be removed. Doing so will reduce the total number of DOM elements in the viewer.
For most documents this patch will probably not make much of a difference performance wise, but for very long (1000+ pages) documents this could help performance especially on lower powered hardware.
Now that [bug 649849](https://bugzilla.mozilla.org/show_bug.cgi?id=649849) has been fixed, adding support for `-moz-appearance: none`, the arrow is now too close to the text in the zoom box. This is currently only an issue in Nightly, but assuming the patch doesn't get backed out, this will soon affect all versions of Firefox.
The only simple solution I could find seems to be removing `*-appearance: none` rules from the CSS. I haven't been able to find any easier solutions that still looks the same with/without bug 649849.
This change does the following:
* Address TODO to remove getEmptyContainer helper.
* Not set container bg-color. The old code is incorrect, causing it to
not have any effect. It sets color to an array (item.color) rather
css string. Also in most cases it would set it to black background
which is incorrect.
* only add border instructions when there is actually a border
* reduce memory consumption by not creating new 3 element arrays for
annotation colors. In fact according to spec, this would be incorrect,
as the default should be "transparent" for an empty array. Adobe
Reader interprets a missing color array as black however.
Note that only Link annotations were actually setting a border style and
color. While Text annotations might have calculated a border they did
not color it. This behaviour is now controlled by the boolean flag.
According to practical experiments, falling back to "Helvetica" when we encounter a non-embedded "[Century Gothic](http://en.wikipedia.org/wiki/Century_Gothic)" `CIDFontType2` font seems to work well.
(Also, the section on Wikipedia about "Printer ink usage" *might* provide some anecdotal evidence that Century Gothic is a fairly standard sans-serif font.)
Obviously this patch doesn't make "Century Gothic" fonts render perfectly, as is often the case with non-embedded fonts, but all the text is now legible in the referenced issues.
Fixes 4722.
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=879561.
