perf: Improve GapJumpingController times (#7921)

Author: avelad

lib/media/gap_jumping_controller.js

@@ -53,6 +53,9 @@ shaka.media.GapJumpingController = class {
     /** @private {shaka.util.EventManager} */
     this.eventManager_ = new shaka.util.EventManager();
 
+    /** @private {boolean} */
+    this.started_ = false;
+
     /** @private {boolean} */
     this.seekingEventReceived_ = false;
 
@@ -90,7 +93,7 @@ shaka.media.GapJumpingController = class {
      */
     this.gapJumpTimer_ = new shaka.util.Timer(() => {
       this.onPollGapJump_();
-    }).tickEvery(this.config_.gapJumpTimerTime);
+    });
   }
 
 
@@ -134,16 +137,22 @@ shaka.media.GapJumpingController = class {
    * @param {number} startTime
    */
   onStarted(startTime) {
+    this.started_ = true;
     if (this.video_.seeking && !this.seekingEventReceived_) {
       this.seekingEventReceived_ = true;
       this.startTime_ = startTime;
     }
+    if (this.gapJumpTimer_) {
+      this.gapJumpTimer_.tickEvery(this.config_.gapJumpTimerTime);
+    }
+    this.onPollGapJump_();
   }
 
   /** Called when a seek has started. */
   onSeeking() {
     this.seekingEventReceived_ = true;
     this.hadSegmentAppended_ = false;
+    this.onPollGapJump_();
   }
 
 
@@ -167,6 +176,10 @@ shaka.media.GapJumpingController = class {
     if (this.video_.readyState == 0) {
       return;
     }
+    // Don't gap jump before playback started
+    if (!this.started_) {
+      return;
+    }
     // Do not gap jump if seeking has begun, but the seeking event has not
     // yet fired for this particular seek.
     if (this.video_.seeking) {