feat: use requestAnimationFrame for scheduleChanges

This allows skipping the frames if the browser is busy doing other 
things, and it will improve the overall experience

Author: aminya

lib/minimap.js

@@ -312,14 +312,18 @@ class Minimap {
     this.pendingChangeEvents = this.pendingChangeEvents.concat(changes)
 
     // Optimisation: If the redraw delay is set to 0, do not even schedule a timer
-    if (!this.redrawDelay) {
-      return this.flushChanges()
+    if (!this.redrawDelay && !this.requestedFlushChanges) {
+      this.requestedFlushChanges = true
+      requestAnimationFrame(() => { this.flushChanges(); this.requestedFlushChanges = false })
     }
 
-    if (!this.flushChangesTimer) {
+    if (!this.flushChangesTimer && !this.requestedFlushChanges) {
       // If any changes happened within the timeout's delay, a timeout will already have been
       // scheduled -> no need to schedule again
-      this.flushChangesTimer = setTimeout(() => { this.flushChanges() }, this.redrawDelay)
+      this.requestedFlushChanges = true
+      this.flushChangesTimer = setTimeout(
+        () => { requestAnimationFrame(() => { this.flushChanges(); this.requestedFlushChanges = false }) }
+      , this.redrawDelay)
     }
   }