This avoids having to store the tool definition in the operator
properties (on redraw).
Now just set the name, note this means we can't show the keymap in the
tool-tip anymore. This will eventually be shown in the status bar.
This was a hard to reproduce bug, but it happens often enough.
Basically the tooltip of the active tool was been invoked when
context had no valid ScrArea which would lead to a crash.
We now just return no tooltip in these cases.
Now that the new 3D viewport draws to a multisample offscreen buffer, there is
no good reason anymore to create an entire multisample window and pay the
performance/memory cost for other regions that don't need it.
GL_MULTISAMPLE now only gets enabled for offscreen buffers, so we don't need
to check for it throughout the UI code anymore.
Differential Revision: https://developer.blender.org/D3062
Move timer and tip out of button code,
now the only requests a tooltip,
passing a creation callback to run.
Needed for manipulators in 2.8,
also helps de-duplicate logic - since we never want
multiple tool-tips showing at once.
This makes code closer to id_override/assent-engine ones, which
introduce a new type of linked data, and hence reserve
ID_IS_LINKED_DATABLOCK to real linked datablocks.
