Introduced dataTransfer.isDrag.
SetData and getData support custom data types on all browsers.
Renamed dataTransfer.isDrag to dataTransfer.method.
Rename dataType to type.
DataTransfer object may have no native event.
Changed paste data structure. Fixed and improved tests.
Tests: check paste event data.
Extracted textToHtml from insertText and use it in firePasteWithDataTransfer.
transformPlainTextToHtml: moved to tools, changed parameters, added tests.
Clean up in firePasteWithDataTransfer.
Changed generateUniqueId and moved to tools.
Code style.
Tests: Clean up tests, split setData-getData tests.
Removed editable#textToHtml.
Introduces editable.transformPlainTextToHtml. Improved comments for tools.transformPlainTextToHtml.
Fixed linter errors.
Fixed getUniqueId and added test for it.
Changelog entry.
Merge branch 't/12168' into major