fix(textbox): Fix IME and touch editing on Android browsers - #25804

…orts-6.7

fix(input): Tap order, iOS touch text editing and Android browser IME (backport #25818, #25619, #25804)

Since unoplatform#25804, BrowserKeyboardInputSource maps a key without a code by its
name, so it raises a soft keyboard's Enter (key "Enter", no code) from its
keydown and keyup. The line break that follows raised the press again, and
a keyup named Enter after a line break raised a second release. The hidden
input now treats such events as ones the source raises.

Takes Uno's servicing/6.8 from 6951c2c up to 5254ace (42 pull
requests). Conflicts, by area:

IME and TextBox (unoplatform#25984, backport of unoplatform#25804; unoplatform#25952, backport of unoplatform#25619;
unoplatform#25976, backport of unoplatform#25818)
- Takes upstream's composition design (unoplatform#25804): the browser's input is
  the source of truth for the text, compositions included. This drops
  the composition parts of the unoplatform#24502 port (90746b8): its
  TypeScript composition handling, the StartIndex/TextChangePending
  event arguments, the IsReadOnly forwarding to the hidden input, and
  its Given_TextBox.BrowserSoftKeyboard tests.
- Keeps the non-IME browser fixes on top of it, in the form their
  master pull requests have on unoplatform#25804: Enter raised once per press and
  tracked by key code (unoplatform#25174, with Given_TextBox.BrowserEnterKey from
  master in place of the Enter tests that lived in the dropped file),
  the iOS refocus on tap (unoplatform#25185), pastes without text and isIOS from
  BrowserInputHelper.
- Moves the unoplatform#26005 MaxLength fixes onto unoplatform#25804's native input path, as
  master has them: a refused browser edit keeps the TextBox's selection,
  TextBoxView.UpdateTextFromNative reports whether the edit went in, and
  the IME keeps its range on the applied text (master be85699, which
  d226897 had ported onto the unoplatform#24502 IME). Adds that commit's browser
  and platform-applied IME tests.
- TextBox.pointers.skia.cs: upstream's file (unoplatform#25619 iOS touch editing,
  unoplatform#25818, unoplatform#25804), with the unoplatform#25126 port (the hold acts when it starts,
  a touch right-tap keeps the caret) in the form master's unoplatform#25126 branch
  has it on unoplatform#25619, including focusing before the iOS hold timer acts
  and its iOS not-focusable test.

Pointers (unoplatform#25976, backport of unoplatform#25818)
- Tapped and RightTapped are raised once the PointerReleased bubbled
  (unoplatform#25818), with the unoplatform#25732 port's window coordinates (2-argument
  routed event args, RawPosition for ContextRequested), as master's
  unoplatform#25732 branch has them.
- The release wrapper of unoplatform#25818 keeps the unoplatform#25126 port's
  StopContextMenuTimer at the start of the release.

DependencyObject (unoplatform#26142, backport of unoplatform#26123)
- Takes upstream, then the code of unoplatform#25839 (97a2f17), which replaces
  this branch's unoplatform#25102 ports (800247f, be41da6, fd40bf9,
  7546379). DependencyObjectStore.Binder.cs, .alc.cs,
  Application.Alc.cs, ResourceDictionary.alc.cs and their tests now
  match unoplatform#25839; this drops 800247f's own
  SingleParentNonFE_Parent_Removes_Value_Then_Next_Parent_Starts_Clean
  test, which unoplatform#25839 doesn't have.

Imaging (unoplatform#25597, unoplatform#25915, unoplatform#25911, unoplatform#25897)
- Keeps this branch's side: it has the later forms of these fixes
  (unoplatform#25124, unoplatform#25559, unoplatform#25633 and unoplatform#26370 ports), where upstream has the
  6.8-only unoplatform#25597 design and earlier snapshots. Upstream's shared
  download, IgnoreImageCache and failed-load fixes are covered by
  SharedImageDecode. Adds upstream's When_Source_Outlives_Brushes test.

ToolTip (unoplatform#26098, backport of unoplatform#25137 and unoplatform#26096)
- Keeps this branch's unoplatform#25137 port and adds unoplatform#26096 in master's form: the
  service releases only a ToolTip it opened, and leaves one the app
  opened during the show delay to the app. Keeps both sides' tests.

Flyout (unoplatform#26062, backport of unoplatform#26060)
- This branch had the same commits already; keeps the "Keep
  non-resizable flyouts in window" port and its tests.

Also removes a helper pair in Given_AccessibleTextBox that both sides
added.

Port of unoplatform#26434 (for unoplatform#26432), commits
faba3ed, 096daef, 8e2644f, b8d2189, edce6fa and
6939ef4, onto the unoplatform#25804 IME design this branch takes
from servicing/6.8 (unoplatform#25984).

- TextCompositionChanged for text the platform applied (WebAssembly,
  Skia Android) waits for the platform's text sync, and isn't raised
  for an update the TextBox refused. The Changed and no-commit Ended
  ranges are clamped to the text. Skia Android reports where its
  composing region starts.
- A composition ends when the hidden input is replaced or detached.
- An edit a BeforeTextChanging handler or a read-only TextBox refuses
  is written back to the input at once, ending the composition.
  Unlike master, this branch does the same for an edit MaxLength
  refuses or a TextChanging handler changes (see below).
- The hidden input is read-only with the TextBox.
- The caret goes back at once after a refused edit.

6.8 differences:
- Master's TextBoxCore.IME.cs, .Input.cs and .cs changes go to
  TextBox.IME.skia.cs, TextBox.skia.cs and TextBox.cs; events are raised
  on the TextBox itself. There is no RichEditBox IME, partial commit or
  CompositionCanceled on 6.8, so those parts are left out.
- Skia Android syncs through a new TextBox.UpdateTextFromNative, the
  6.8 counterpart of master's IImeSessionHost.UpdateTextFromNative. It
  raises the held TextCompositionChanged, and compares the editable's
  \n line breaks as the TextBox's \r, as master's
  IsNativeEchoOfCurrentText does.
- The read-only input follows TextBox.IsReadOnly through
  OnIsReadonlyChangedPartial; UpdateProperties, which only sets the
  enter key hint on 6.8, now also sets readOnly or re-enters the input.

With this branch's port of unoplatform#26005 (be85699):
- A refused platform sync puts the composition range back on the text
  that is there (unoplatform#26005), and raises TextCompositionChanged
  for that range only when it isn't the last range raised. The refused
  update's own range is never raised (unoplatform#26434).
- While a composition holds text the TextBox refused past MaxLength
  (reconciled when it ends), the hidden input's selectionchange isn't
  reported: its offsets are in that text, not in the TextBox's. Without
  this, the input's caret replaced the one edce6fa restores at once.
- ApplyNativeInput keeps unoplatform#26005's handling of a refused
  edit's pending selection.

Like Android's own LengthFilter (and this branch before the catch-up),
a composition edit the TextBox doesn't keep as the keyboard applied it
(MaxLength, a TextChanging filter, as well as BeforeTextChanging and
read-only) writes the TextBox's text back at once and ends the
composition, on WebAssembly and on Skia Android. Master keeps a
MaxLength or TextChanging refusal in the input until the composition
ends, so a CJK conversion can bring it back within the limit. Gboard
composes every Latin word, though, so the refused letters stayed in the
input for the whole word: its suggestions were built on them, and
Backspace deleted them before it reached the TextBox's text. A
conversion past the limit is lost here, as with Android's LengthFilter.
When_Browser_Ime_Composes_With_TextChanging_Filter (unoplatform#25804)
and the two conversion tests of unoplatform#26434 now expect that,
and When_Browser_Ime_Composes_Word_Past_MaxLength_Then_Input_Keeps_The_Limit
covers the Gboard case.

Adds tests for a refused Skia Android sync, \n line breaks in its sync,
and a refused composition followed by another before the dispatcher
runs.

Port of the review round of unoplatform#26434 (commits 0e475cdb9e
and 73279a2cf1 there) onto this branch's write-back.

- Narrower rule: the input or the native editable takes the TextBox's
  text back at once, ending the composition, only when the TextBox
  refused the edit or kept text of another length (MaxLength, a length
  limit). A change that keeps the length (an upper-case TextChanging
  filter) waits for the end of the composition again, as
  unoplatform#25804 made it, so an IME can still convert it:
  When_Browser_Ime_Composes_With_TextChanging_Filter is back to
  servicing/6.8's version. TextBox.MustReturnTextToNative holds the
  rule, and compares without allocating.
- Skia Android's EndBatchEdit no longer reads ActiveTextBox again after
  the sync, which runs app handlers that may move focus or clear it
  (a null reference in the IME callback): it writes back only to the
  TextBox it synced, and only after the IME changed the text. The
  write-back is one batch for the listeners, so a TextCompositionEnded
  handler that sets the text again is written after it.
- The comments no longer describe this as what Android's LengthFilter
  does, and the remaining ones about the end-of-composition
  reconciliation say which edits it still covers.
- When_Browser_Ime_Composes_Past_MaxLength and
  When_Browser_Ime_Composition_Coerced_Shorter_Than_Its_Start check the
  input right after the update, and that the browser's late
  compositionend changes nothing.

TextBox.UpdateTextFromNative already kept the TextBox's caret on a
refused sync (the applied check of unoplatform#26005), unlike master's;
When_IME_Platform_Sync_Refused_Then_Caret_Stays covers it here too.
6.8 has no RichEditBox IME, so the RichEditBox part doesn't apply.

A composition edit the TextBox refused stayed in the hidden input until
the composition ended, unless a BeforeTextChanging handler or a
read-only TextBox refused it: an edit MaxLength refused, or that a
length limit put back, was left for the end of the composition, so that
a CJK conversion could still bring it back within the limit. Gboard
composes every Latin word, though, so the letters typed past MaxLength
stayed in the input for the whole word: the keyboard built its
suggestions on them, and Backspace deleted them before it reached the
TextBox's text.

This replaces that trade-off. When the TextBox keeps text of another
length than the input's (MaxLength, a length limit), or refuses a change
of the input's text and keeps its own previous text, its text goes back
to the input at once and the composition ends, so the keyboard builds
its next keystrokes and suggestions on the text the TextBox kept. The
input now reports its value at the previous sync with each edit, so the
same text reported again (a caret move inside the preedit) doesn't count
as a refusal while a same-length filter keeps the two texts apart. Kana
typed past a limit is cut at the limit rather than converted later. A
change that keeps the length (an upper-case filter) still waits for the
end of the composition, as unoplatform#25804 made it, so an IME can
still convert it. ImeSessionCoordinator.MustReturnTextToNative holds the
rule.

RichEditBox gets the same rule, so an edit it refuses or cuts to its
text limit is written back, and its CharacterCasing waits for the end of
the composition. ApplyNativeInput no longer has to tell a refusal from a
handler's put-back text, so its result and the text change count go.

Tests: When_Browser_Ime_Converts_Past_MaxLength and
When_Browser_Ime_Converts_Past_TextChanging_Limit become
When_Browser_Ime_Kana_Composes_Past_MaxLength and
When_Browser_Ime_Kana_Composes_Past_TextChanging_Limit;
When_Browser_Ime_Composes_Word_Past_MaxLength_Then_Input_Keeps_The_Limit
covers the Gboard case and
Given_RichEditBox.When_Wasm_Composition_Past_MaxLength_Is_Written_Back
the RichEditBox, with
When_Wasm_Composition_Past_MaxLength_In_The_Middle_Keeps_The_Caret and
When_Wasm_Composition_With_Upper_Casing_Stays_Open.
When_Browser_Ime_Filtered_Composition_Reported_Again_Stays_Open,
When_Browser_Ime_Same_Length_Replacement_Is_Refused and the table test
When_Native_Text_Is_Compared_To_The_Kept_Text cover the rule's clauses.
When_Browser_Ime_Composes_Past_MaxLength and
When_Browser_Ime_Composition_Coerced_Shorter_Than_Its_Start now check
the input right after the update, and that the browser's late
compositionend changes nothing.