Add two new size variants for Valo, tiny and huge

Available as additional style names for buttons, text fields/text
areas, combo boxes, date fields and labels.

Change-Id: I12f36935a690f5bf3f12333f5bd4ac986d4efd1f
ExtraWindowShownWaiAria test upgrade (#14292)

Change-Id: I83f0d08850d2e03008601f10043314c00818bdaa
Valo Tree Drag & Drop styles broken (#14360)

Change-Id: Iafee03aaea3266ab32edb407e605ff3d8de474e1
TextFieldRelativeWidth test upgrade (#14292)

Change-Id: Ia879f22f171c97fd614a92526db3cd00f35d9d27
Add new "colored" style for Label (Valo)

Makes any Label text colored, by default the same as $v-selection-color.

Modify the Forms and Labels examples to use the new style, and remove
the fixed color from “light” style form layout for header labels.

Change-Id: I27a4fce56b1f734aa5c2c837bf1684284b0d96cc
Make read only textfield visually different from normal text fields

If the background color of the app is the same as the textfield
background color, make the textfield background color slightly darker.

Change-Id: I4870c3e396cdd8c586bfd3f0e812cf1f5ebab1eb
PopupDateFieldExtendedRange test upgrade (#14292)

Change-Id: I62f3f17cfbd5ddb5e1cd1b6085f4437fa49cfad1
Modularize menubar mixins and add submenu indicator for top level items

Refactored menubar mixins so that less overrides are necessary from
normal button styles, and so that custom colored and custom sized menu
bars are possible.

Add new examples to test app for “drop down buttons” and “split
buttons” using MenuBar.

Change-Id: I2b0b76817d1c9119f82b2c2f4d7e5b95a9f05a5c
Remove unnecessary negative border radius declarations from menu bar (Valo)

Change-Id: I3739cdacf6a117cd0d75cab3566a82ee0fedd6bd
Make test stable again

Change-Id: I1e02ce31ec7f0235158a5b04812c031e040c7ba2
Update GWT version (#14051)

The new version fixes source map generation when collapse-all-properties is on

Change-Id: I4bcf9bd64a8dd9bc2e65c225df9ba4313e3d4194
Merge remote-tracking branch 'origin/master' into 7.3