Impossible to place an editable selection inside empty elements

[rniwa]

4136be1

Impossible to place an editable selection inside empty elements
https://bugs.webkit.org/show_bug.cgi?id=15256

Reviewed by NOBODY (OOPS!).

Use the uncanonicalized selection ends for text insertion.

* LayoutTests/editing/deleting/delete-3775172-fix-expected.txt:
* LayoutTests/editing/execCommand/5142012-3-expected.txt:
* LayoutTests/editing/execCommand/typing-should-not-trigger-scrolling-when-selection-is-visible.html:
* LayoutTests/editing/inserting/4840662.html:
* LayoutTests/editing/inserting/5156401-2.html:
* LayoutTests/editing/inserting/5510537-expected.txt:
* LayoutTests/editing/inserting/editable-html-element-expected.txt:
* LayoutTests/editing/inserting/editing-empty-divs-expected.txt:
* LayoutTests/editing/inserting/insert-3778059-fix-expected.txt:
* LayoutTests/editing/inserting/insert-at-end-01-expected.txt:
* LayoutTests/editing/inserting/insert-at-end-02-expected.txt:
* LayoutTests/editing/inserting/insert-before-link-1-expected.txt:
* LayoutTests/editing/inserting/insert-html-crash-01-expected.txt:
* LayoutTests/editing/inserting/typing-003-expected.txt:
* LayoutTests/editing/inserting/typing-around-image-001-expected.txt:
* LayoutTests/editing/selection/4983858-expected.txt:
* LayoutTests/editing/spelling/centering-misspelling-dots-expected.txt:
* LayoutTests/editing/spelling/misspelling-dots-dont-extend-beyond-words-expected.txt:
* LayoutTests/editing/style/remove-underline-across-paragraph-expected.txt:
* LayoutTests/editing/style/remove-underline-across-paragraph-in-bold-expected.txt:
* LayoutTests/editing/style/remove-underline-after-paragraph-expected.txt:
* LayoutTests/editing/style/remove-underline-after-paragraph-in-bold-expected.txt:
* LayoutTests/editing/style/remove-underline-expected.txt:
* LayoutTests/editing/style/remove-underline-from-stylesheet-expected.txt:
* LayoutTests/editing/style/remove-underline-in-bold-expected.txt:
* LayoutTests/editing/style/typing-style-003-expected.txt:
* LayoutTests/editing/style/unbold-in-bold-expected.txt:
* LayoutTests/editing/style/underline-expected.txt:
* LayoutTests/editing/unsupported-content/list-type-before.html:
* LayoutTests/editing/unsupported-content/table-type-before-expected.txt:
* LayoutTests/platform/mac/editing/inserting/insert-text-at-tabspan-003-expected.txt:

* Source/WebCore/editing/CompositeEditCommand.cpp:
(WebCore::CompositeEditCommand::positionOutsideTabSpan): Consider the case where the anchor node
is the WebKit tab span element.

* Source/WebCore/editing/InsertTextCommand.cpp:
(WebCore::InsertTextCommand::positionInsideTextNode): Consider the text node before or after
the position.
(WebCore::InsertTextCommand::doApply): Use the uncanonicalized selection start as the start position.
Also don't rebalance whitespaces at the end if the starting position was not a candidate (e.g.
we're at a visually empty text node) and the inserted text didn't end with a whitespace.

4136be1

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk
✅ 🧪 webkitperl	❌ 🧪 ios-wk2	✅ 🧪 api-mac	❌ 🧪 gtk-wk2
	❌ 🧪 api-ios	❌ 🧪 mac-wk1	✅ 🧪 api-gtk
	✅ 🛠 tv	❌ 🧪 mac-wk2
	✅ 🛠 tv-sim	❌ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 4136be1)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk
✅ 🧪 webkitperl	❌ 🧪 ios-wk2	✅ 🧪 api-mac	❌ 🧪 gtk-wk2
	❌ 🧪 api-ios	❌ 🧪 mac-wk1	✅ 🧪 api-gtk
	✅ 🛠 tv	❌ 🧪 mac-wk2
	✅ 🛠 tv-sim	❌ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim