Chase: Use timers for timing instead of counting cycles

Counting cycles is an incredibly unreliable way of timing animations. Use timers
instead.

Fixes #545.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

src/kaleidoscope/plugin/LEDEffect-Chase.cpp

@@ -18,15 +18,16 @@
 
 namespace kaleidoscope {
 namespace plugin {
+
 void LEDChaseEffect::update(void) {
   if (!Kaleidoscope.has_leds)
     return;
 
-  // Check to see if it's time to change the positions of the red and blue lights
-  if (current_chase_counter++ < chase_threshold) {
+  uint16_t now = Kaleidoscope.millisAtCycleStart();
+  if ((now - last_update_) < update_delay_) {
     return;
   }
-  current_chase_counter = 0;
+  last_update_ = now;
 
   // The red LED is at `pos`; the blue one follows behind. `chase_sign` is either +1 or
   // -1; `chase_pixels` is the gap between them.

src/kaleidoscope/plugin/LEDEffect-Chase.h

@@ -24,6 +24,13 @@ class LEDChaseEffect : public LEDMode {
  public:
   LEDChaseEffect(void) {}
 
+  uint16_t update_delay() {
+    return update_delay_;
+  }
+  void update_delay(uint16_t delay) {
+    update_delay_ = delay;
+  }
+
  protected:
   void update(void) final;
 
@@ -31,8 +38,8 @@ class LEDChaseEffect : public LEDMode {
   int8_t pos = 0;
   int8_t chase_sign = 1; //negative values when it's going backwar
   uint8_t chase_pixels = 5;
-  uint8_t current_chase_counter = 0;
-  static const uint8_t chase_threshold = 150;
+  uint16_t update_delay_ = 150;
+  uint16_t last_update_ = 0;
 };
 }
 }