UE-9331 - Missing icons for BP component classes when restarting editor
Moved the code to work out the correct class icon for a Blueprint or asset data into FClassIconFinder so that it can be shared between the asset thumbnails and the components context menu.
Added an extra IconClass member to FComponentClassComboEntry so that unloaded Blueprints can set this appropriately despite having a null ComponentClass.
[CL 2451813 by Jamie Dale in Main branch]
Improvements to the way thumbnails are shown in the Content Browser
UE-7184 - Show game c++ classes and engine c++ classes in the content browser
C++ classes and Blueprints now both show you either a live-thumbnail (for asset types), or a class thumbnail for their class type. If showing a live-thumbnail, they also show a mini class icon at the bottom right of the thumbnail.
This iconography change has been applied to all asset types, and they now show you their asset type icon on the colored overlay, rather than show you the asset type text. They will still fallback to using the asset type text if there is no icon available for the asset type.
[CL 2419540 by Ben Marsh in Main branch]
Remove special case icon code in Class Picker 'common' classes
Add lots of placeholder icons for class types that were missing them (AIController, GameMode, HUD, PlayerController...)
Fix class lookup too allow different icon for Actor and Object based classes
Remove some unused/duplicate icons
[CL 2419429 by Ben Marsh in Main branch]
* Moved Slate.h into SlateBasics.h and began shifting less commonly used headers into SlateExtras.h.
* Slate.h now simply includes SlateBasics.h and SlateExtras.h.
* Slate.h includes a deprecated warning now to indicate that SlateBasics.h + specific includes should be used instead.
* Moved dozens of inlined functions using Slate widgets into .cpp files to avoid header dependencies.
* All code samples now include SlateBasics.h and SlateExtras.h so future shifts will not break most those projects, but not trigger the deprecation warning of including Slate.h.
#BUN
[CL 2329610 by Wes Hunt in Main branch]
FClassIconFinder can now find thumbnails for classes. Added many more asset type icons should they be required. Updated the AssetBackground and ThumbnailShadow images to make them a bit cleaner and smoother.
Reviewed by Tom Sarkanen, Matt Kuhlenschmidt
[CL 2061990 by Andrew Rodham in Main branch]
