This was already being used for sb3s and sprite3s, but the code was repeated in different places. Make a single helper that downloads blobs, and make all download paths use it.

We can't rely on refreshWorkspace always causing a toolbox update, so make sure to update the toolbox manually if it is needed.

This fixes a problem where having a non-default locale set during the initial load would display the blocks in the default toolbox in the wrong language, because the toolbox recycling toggle in setLocale does not work on initial load because there is no editing target to refresh.

Since the common use-case is download/edit/re-upload, and we do not want to explode the storage size of assets (which are considerably larger with fonts inlined), just do what scratch2 did and do not inline the fonts. This is not ideal if kids want to use the costumes for other purposes, but until we can create a way to strip inlined fonts before uploading to the asset server, this is the conservative way to go.

This fixes the issue where you could not see any new variables or custom block callers, as well as fixing the issue where the toolbox did not update from then on.

This invalidates the toolbox XML when switching back to the code tab after e.g. renaming a costume, making the code tab

Need to store the rendered xml because the props can change while the blocks tab is hidden, but we re-render based on what was rendered, not the previous props (which may not have been rendered).

This is similar to the `ThrottledPropertyHOC` in that there may be prop changes that do not get rendered, but in this case for a different reason.

This increases the performance of switching between code and other editor tabs, as well as improving the "See Inside" performance. It makes switching to the code tab as fast as switching between sprites.

It also avoids repeating the costly object spread, which becomes a problem for projects with a lot of sprites

Use PureComponent instead since it is a simple shouldComponentUpdate check now.

This reverts commit 97f8eb63, reversing
changes made to 2e017f06.

There was a useability issue discovered in testing where trying to trim a sound to be of zero length would fail, but just leave the trimmers active. Clear them out, since the trim is invalid

This is used because the sortable drop is also used for general dropping as well as sorting drop, so you need to be able to drop into a sortable list that does not contain any items.

Make the corresponding reorder code be more careful to check if there is a newIndex.

On slow machines it was possible to double click record before the chunk of samples had been processed, causing zero-length audio buffers

https://github.com/LLK/scratch-gui/pull/4312 had a function name conflict with the existing code. This change fixes that by renaming the conflicting function, and removes redundant code.

Move the onClick handler to the overlay wrapper so that the whole stage is clickable to start the project instead of just the green flag button

www needs to know when a project finishes loading so that remixing can be disabled while the project is in a state that cannot be remixed.

Browsers other than IE will be allowed to load the GUI.
However, if there is an error, the error boundary will display an unsupported browser message recommending they update to the latest version of a supported browser.

For the purposes of this PR, ‘supported’ means you can load the gui (anything other than IE), and recommended is just the browsers that meet our minimum requirements for Chrome, Firefox, Edge and Safari.

The playground now displays this on startup when in Scratch Desktop
simulation mode.