Confirmed with 58.0.3029.110 (Official Build) (64-bit) on Win

FrameSelection::DidSetSelectionDeprecated() dispatches "selectionchange" at end
of function by:
  frame_->DomWindow()->EnqueueDocumentEvent(
      Event::Create(EventTypeNames::selectionchange));

The root cause is Blink relocates selection by CharacterData::deleteData() during
processing backspace.

It seems we need to know whether selection is relocated or not.
Then dispatching "selectionchange" in Editor::ChangeSelectionAfterCommand().


# Relocation of Selection
blink::SelectionEditor::DidFinishTextChange(const blink::PositionTemplate<blink::EditingAlgorithm<blink::NodeTraversal> > & new_base, const blink::PositionTemplate<blink::EditingAlgorithm<blink::NodeTraversal> > & new_extent) Line 142
blink::SelectionEditor::DidUpdateCharacterData(blink::CharacterData * node, unsigned int offset, unsigned int old_length, unsigned int new_length) Line 276
blink::SynchronousMutationNotifier::NotifyUpdateCharacterData(blink::CharacterData * character_data, unsigned int offset, unsigned int old_length, unsigned int new_length) Line 48
blink::CharacterData::SetDataAndUpdate(const WTF::String & new_data, unsigned int offset_of_replaced_data, unsigned int old_length, unsigned int new_length, blink::CharacterData::UpdateSource source) Line 194
blink::CharacterData::deleteData(unsigned int offset, unsigned int count, blink::ExceptionState & exception_state) Line 138
blink::DeleteFromTextNodeCommand::DoApply(blink::EditingState * __formal) Line 59
blink::CompositeEditCommand::ApplyCommandToComposite(blink::EditCommand * command, blink::EditingState * editing_state) Line 191
blink::CompositeEditCommand::DeleteTextFromNode(blink::Text * node, unsigned int offset, unsigned int count) Line 535
blink::DeleteSelectionCommand::DeleteTextFromNode(blink::Text * node, unsigned int offset, unsigned int count) Line 561
blink::DeleteSelectionCommand::HandleGeneralDelete(blink::EditingState * editing_state) Line 634
blink::DeleteSelectionCommand::DoApply(blink::EditingState * editing_state) Line 1138
blink::CompositeEditCommand::ApplyCommandToComposite(blink::EditCommand * command, blink::EditingState * editing_state) Line 191
blink::TypingCommand::DeleteSelectionIfRange(const blink::VisibleSelectionTemplate<blink::EditingAlgorithm<blink::NodeTraversal> > & selection, blink::EditingState * editing_state, bool smart_delete, bool merge_blocks_after_delete, bool expand_for_special_elements, bool sanitize_markup) Line 192
blink::TypingCommand::DeleteKeyPressed(blink::TextGranularity granularity, bool kill_ring, blink::EditingState * editing_state) Line 848
blink::TypingCommand::DeleteKeyPressed(blink::Document & document, unsigned int options, blink::TextGranularity granularity) Line 212
blink::Editor::DeleteWithDirection(blink::DeleteDirection direction, blink::TextGranularity granularity, bool kill_ring, bool is_typing_action) Line 435
blink::ExecuteDeleteBackward(blink::LocalFrame & frame, blink::Event * __formal, blink::EditorCommandSource __formal, const WTF::String & __formal) Line 741
blink::Editor::Command::Execute(const WTF::String & parameter, blink::Event * triggering_event) Line 2956
blink::Editor::Command::Execute(blink::Event * triggering_event) Line 2959
blink::Editor::HandleEditingKeyboardEvent(blink::KeyboardEvent * evt) Line 54
blink::Editor::HandleKeyboardEvent(blink::KeyboardEvent * evt) Line 84


# SetSelection after character changed
FrameSelection::SetSelectionDeprecated(const blink::SelectionTemplate<blink::EditingAlgorithm<blink::NodeTraversal> > & passed_selection, unsigned int options, blink::TextGranularity granularity) Line 221
FrameSelection::SetSelection(const blink::SelectionTemplate<blink::EditingAlgorithm<blink::NodeTraversal> > & passed_selection, unsigned int options, blink::CursorAlignOnScroll align, blink::TextGranularity granularity) Line 188
Editor::ChangeSelectionAfterCommand(const blink::SelectionTemplate<blink::EditingAlgorithm<blink::NodeTraversal> > & new_selection, unsigned int options) Line 1514
Editor::AppliedEditing(blink::CompositeEditCommand * cmd) Line 956
TypingCommand::TypingAddedToOpenCommand(blink::TypingCommand::ETypingCommand command_type_for_added_typing) Line 537
TypingCommand::DeleteKeyPressed(blink::TextGranularity granularity, bool kill_ring, blink::EditingState * editing_state) Line 852
TypingCommand::DoApply(blink::EditingState * editing_state) Line 474
CompositeEditCommand::Apply() Line 143
TypingCommand::DeleteKeyPressed(blink::Document & document, unsigned int options, blink::TextGranularity granularity) Line 217
Editor::DeleteWithDirection(blink::DeleteDirection direction, blink::TextGranularity granularity, bool kill_ring, bool is_typing_action) Line 435
ExecuteDeleteBackward(blink::LocalFrame & frame, blink::Event * __formal, blink::EditorCommandSource __formal, const WTF::String & __formal) Line 741
Editor::Command::Execute(const WTF::String & parameter, blink::Event * triggering_event) Line 2956
Editor::Command::Execute(blink::Event * triggering_event) Line 2959
Editor::HandleEditingKeyboardEvent(blink::KeyboardEvent * evt) Line 54

Tested the issue on windows 7 , Mac os 10.12.4 and ubutu 14.04 using chrome M58 #58.0.3029.110 and chrome canary M60 #60.0.3110.0 and issue is reproduced.

Issue is regression issue broken in M58 .

Using the per-revision bisect providing the bisect results,
Good build: 58.0.3012.0(Revision: 450199).
Bad build: 58.0.3013.0 (Revision: 450530).

You are probably looking for a change made after 450369 (known good), but no later than 450370 (first known bad).

CHANGELOG URL:

The script might not always return single CL as suspectas some perf builds might get missing due to failure.

 https://chromium.googlesource.com/chromium/src/+log/18375370aff250f59f5ef624ecf686d860377ece..d892f9592860691ae9a782c12260c94ed6bd1a63

From the CL above, assigning the issue to the concern owner 

@yosin- Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Review-Url: https://codereview.chromium.org/2680943004

Thanks!

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

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