Fix content rendering (the first sentence was omitted if there is no empty line between the title and the first paragraph).

* Test updates

- updated screenshots for Firefox, IE, and Chrome
- updated Firefox and Chrome version numbers

- ScrollbarBundle: removed delays in scroll handling that were only
needed for IE8, added possibility to update offsetSize and scrollSize at
the same time in order to avoid triggering unnecessary scrollbar
visibility change events during the intermediate state.
- ColumnConfigurator: added new method that allows setting column widths
without triggering element size recalculations.
- EscalatorProxy: added implementation of the new method to
ColumnConfigurationProxy.
- Escalator: switched to use new methods in ScrollbarBundle and
ColumnConfigurator, added a pixel to a scrollbar offsetSize calculation
that was for some reason consistently one pixel too low, removed
duplicate method calls from sectionHeightCalculated handling as those
are already handled by the calling method and can cause incorrect
intermediate state and unnecessary scrollbar visibility change events,
added implementation of the new method to ColumnConfigurationImpl with
the element size recalculations made optional.
- Grid: updated column minimum width calculations to take into account
the potential presence of a resize handle, updated expand ratio handling
to not trigger element size recalculations until the entire handling is
finished.
- Test for column width handling when there are multiple columns with
setMinimumWidthFromContent(false)

Fixes #12139

Use generated IDs for MenuItems when an ID is set for MenuBar. Tying the ID to MenuBar's ID helps with the possible case of having multiple MenuBars on the same view and avoids to have excess id's when not needed.

Fixes: https://github.com/vaadin/framework/issues/8186

https://github.com/vaadin/framework/issues/12113

Otherwise opening a Grid editor can cause ApplicationConnection to get
stuck in 'active' state even if no actual scroll position processing is
ongoing, which in turn causes TestBench delays when it tries to wait
until ApplicationConnection indicates that everything necessary has been
processed.

Fixes: #12106

Fixes: https://github.com/vaadin/framework/issues/7773

This is needed to get /UIDL working behind a reverse proxy. Without the change pathInfo would be "/UIDL" but prefix would be "/UIDL/" in line 105.

Co-authored-by: Anna Koskinen <anna@vaadin.com>

Pick from https://github.com/vaadin/framework/pull/12084

Hibernate Validator 5+ requires
- Validation API 2+
- explicit Expression Language dependency

Fixes #10437

* Add 1px buffer to Escalator column natural widths.

The purpose of the buffer is to avoid subpixel handling issues,
especially when zoomed in or out.

In case fractions need to be adjusted for browser compatibility, round
up to ensure the contents have the space they need.

Fixes #12048

* Fix to natural column width calculations in Table footer.

NOTE: components within row generator are not an officially supported feature and can cause issues within your application.

Fixes #11235

* Update release-note template for 8.12.0.alpha1

* Add a regression test for Table's RowGenerator feature.

There used to be a TB2 test for this once upon a time, but for some
reason that never got converted into a TB3 test before getting removed.

* Explicitly remove old dataprovider listener when new one is set

If not done, this can cause memory leakage

* Formatting

* Fixed coding style

* Take into account further scenarios

Component maybe detached permanently and thus data provider listener needs to be remove in detach. Also if this is only momentary remove from layout add back cycle, re-setup is needed in attach, in case it was not already setup before attaching by setDataProvider.

* Change super.detach() call order

* Added null check to getDataProvider

* Setting dataProviderListener to null on detach

* Removing listener only if it exists

* Fix

It is possible when Vaadin 8 is used with MPR, that ui.getCurrent().getSession() returns null.

See: https://github.com/vaadin/multiplatform-runtime/issues/5

There might be pending requests in the queue when a resync request is
made (e.g. through a theme change). This can cause conflicts if the
resync request is handled immediately. Therefore the resync request
should also be added to the queue and only get resolved when
doSendInvocationsToServer() gets triggered again.

Fixes #11954

- If the Grid has any columns with non-fixed widths, the presence of a
vertical scrollbar affects the column width calculations. Horizontal
scrollbar should only be shown when actually needed.

Fixes #12049

Delayed size changes caused by added or removed scrollbars should be
taken into account.

Calculate number of the week in the year based on Date. Note, support for "ww" is missing from GWT DateTimeFormat and java.util.Calendar is not supported in GWT, hence DIY method is needed.

Fixes: #10603

Adopted from https://github.com/vaadin/flow/pull/8567

Fixes #12029

* Add tests

* Fix getVisibleFrozenColumnCount() if SelectionMode is multi

* Update chrome version to 83

* Update screenshots

* Fix ComboBox in read-only mode allowing value change by user

Fixes #12021

* Fix popup hiding condition

Co-authored-by: Tatu Lund <tatu@vaadin.com>

* Add autocomplete prevention to DateField

Autocomplete popup will interfere DateField's own popup

* Adding disableBrowserAutocomplete(..) in WidgetUtil

* Change VComboBox to use WidgetUtil.disableBrowserAutocomplete(..)

* Change to use WidgetUtil.disableBrowserAutocomplete(..)

* Change VFilterSelect to use WidgetUtil.disableBrowserAutocomplete(..)

* Adding WidgetUtil.disableBrowserAutocomplete to VTextualDate

* Adding missing import

* Adding missing import