Grid supports state-override of isScrolling value via new isScrolling…

… prop. This enables cache-while-scrolling of cells when used with WindowScroller. (@olavk - bvaughn#639)

🐛 Small accessibility fix to MultiGrid so that focus outline shows th…

…rough by default for main (bottom/right) Grid. Top and left Grids are also not tab-focusable by default now since they are scroll-observers anyway.

✨  Added columnWidth parameter to ColumnSizer and deprecated getColumnWidth callback. The callback was not necessary since columnWidth doesn't change without a re-render and fixed number values perform better in Grid due to some internal optimizations anyway.

* 🐛 Edge-case InfiniteLoader bug fix; prevent jumping to the first ro…

…w when scrolling fast. ([@reVrost](https://github.com/reVrost) - [bvaughn#632](bvaughn#632))

* 🐛  Reverted unexpected regression from [bvaughn#616](bvaughn#616) until a safer fix can be found.

* 🎉 New Masonry component optimized for Pinterest-style layouts. Chec…

…k out the docs (https://github.com/bvaughn/react-virtualized/blob/master/docs/Masonry.md) and demo page (https://bvaughn.github.io/react-virtualized/#/components/Masonry) to learn more. (bvaughn#618)

* 🎉 MultiGrid supports scrollLeft and scrollTop props for controlled scrolling. (@julianwong94 - bvaughn#624)
* 🎉 New direction parameter passed to overscanIndicesGetter with values "horizontal" or "vertical". (@offsky - bvaughn#629)
* ✨ Replaced inline require statement with header import in Grid for better integration with the Rollup module bundler. (@odogono - bvaughn#617)
* 🐛 Improved guard for edge-case scrolling issue with rubberband scrolling in iOS. (@dtoddtarsi - bvaughn#616)
* ✨ Replaced getBoundingClientRect() with slightly faster offsetWidth and offsetHeight inside of AutoSizer.
* ✨ AutoSizer no longer re-renders nor calls onResize callback unless width and/or height have changed (depending on which properties are being watched).

Added resetLoadMoreRowsCache method to InfiniteLoader to reset any ca…

…ched data about loaded rows. This method should be called if any/all loaded data needs to be refetched (eg a filtered list where the search criteria changes). (bvaughn#612)

CellMeasurer should work better out of the box with MultiGrid.

CellMeasurerCache should return correct values from rowHeight and columnWidth functions when keyMapper is used. (bvaughn#613)

🐛 Fixed small scrollbar offset bug in MultiGrid. (bvaughn#609)

9.2.1

* 🐛 Fixed potential scrollbar offset bug in MultiGrid by giving top and left Grids a little extra space to scroll into. (bvaughn#535)

9.2.0:

* 🎉 New Table prop, headerRowRenderer. (@kaoDev - bvaughn#600)
* 🎉 All Table event handlers now receive a named event params (@paulbrom - bvaughn#605)
* 🎉 Aria roles for Table improved to specify role="row" for table rows and role="rowgroup" for iner Grid. (@jchen527 - bvaughn#607)
* 🐛 Calling scrollToRow for List or Table no longer potentially messes up horizontal scroll position. (bvaughn#603)

🎉 Public method 'setScrollIndexes' added to 'ArrowKeyStepper' to enab…

…le easier overrides of current/default focused cell.

✨ Replaced 'value instanceof Function' checks with 'typeof value === 'function'' for improved robustness with iframes/frames/popups.

🐛 'Grid' props 'scrollToColumn' and 'scrollToRow' as well as 'Collection' prop 'scrollToCell' now default to '-1' to avoid false positives from 'null >= 0' check.