Add feature flags for scheduler experiments

Author: rickhanlonii

packages/scheduler/src/SchedulerFeatureFlags.js

@@ -8,4 +8,6 @@
 
 export const enableSchedulerDebugging = false;
 export const enableIsInputPending = false;
+export const enableIsInputPendingContinuous = false;
 export const enableProfiling = __VARIANT__;
+export const schedulerYieldMs = 5;

packages/scheduler/src/forks/Scheduler.js

@@ -11,6 +11,9 @@
 import {
   enableSchedulerDebugging,
   enableProfiling,
+  enableIsInputPending,
+  enableIsInputPendingContinuous,
+  schedulerYieldMs,
 } from '../SchedulerFeatureFlags';
 
 import {push, pop, peek} from '../SchedulerMinHeap';
@@ -36,8 +39,6 @@ import {
   startLoggingProfilingEvents,
 } from '../SchedulerProfiling';
 
-import {enableIsInputPending} from '../SchedulerFeatureFlags';
-
 let getCurrentTime;
 const hasPerformanceNow =
   typeof performance === 'object' && typeof performance.now === 'function';
@@ -418,7 +419,7 @@ let taskTimeoutID = -1;
 // thread, like user events. By default, it yields multiple times per frame.
 // It does not attempt to align with frame boundaries, since most tasks don't
 // need to be frame aligned; for those that do, use requestAnimationFrame.
-let yieldInterval = 5;
+let yieldInterval = schedulerYieldMs;
 let deadline = 0;
 
 // TODO: Make this configurable
@@ -444,7 +445,12 @@ function shouldYieldToHost() {
       // regardless, since there could be a pending paint that wasn't
       // accompanied by a call to `requestPaint`, or other main thread tasks
       // like network events.
-      if (needsPaint || scheduling.isInputPending()) {
+      if (
+        needsPaint ||
+        scheduling.isInputPending({
+          includeContinuous: enableIsInputPendingContinuous,
+        })
+      ) {
         // There is either a pending paint or a pending input.
         return true;
       }
@@ -489,7 +495,7 @@ function forceFrameRate(fps) {
     yieldInterval = Math.floor(1000 / fps);
   } else {
     // reset the framerate
-    yieldInterval = 5;
+    yieldInterval = schedulerYieldMs;
   }
 }
 

packages/scheduler/src/forks/SchedulerFeatureFlags.www.js

@@ -8,8 +8,10 @@
 
 export const {
   enableIsInputPending,
+  enableIsInputPendingContinuous,
   enableSchedulerDebugging,
   enableProfiling: enableProfilingFeatureFlag,
+  schedulerYieldMs,
 } = require('SchedulerFeatureFlags');
 
 export const enableProfiling = __PROFILE__ && enableProfilingFeatureFlag;