diff --git a/image/DecodePool.cpp b/image/DecodePool.cpp
index 2781bcc5a314..b63322691452 100644
--- a/image/DecodePool.cpp
+++ b/image/DecodePool.cpp
@@ -142,9 +142,9 @@ class DecodingTask final : public Task {
                                           : EventQueuePriority::RenderBlocking),
         mTask(aTask) {}
 
-  bool Run() override {
+  TaskResult Run() override {
     mTask->Run();
-    return true;
+    return TaskResult::Complete;
   }
 
 #ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
diff --git a/js/xpconnect/src/XPCJSContext.cpp b/js/xpconnect/src/XPCJSContext.cpp
index 9b5fcd84127c..e1e5a7ecef54 100644
--- a/js/xpconnect/src/XPCJSContext.cpp
+++ b/js/xpconnect/src/XPCJSContext.cpp
@@ -1165,9 +1165,9 @@ CycleCollectedJSRuntime* XPCJSContext::CreateRuntime(JSContext* aCx) {
 
 class HelperThreadTaskHandler : public Task {
  public:
-  bool Run() override {
+  TaskResult Run() override {
     JS::RunHelperThreadTask();
-    return true;
+    return TaskResult::Complete;
   }
   explicit HelperThreadTaskHandler()
       : Task(Kind::OffMainThreadOnly, EventQueuePriority::Normal) {
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index a1722c08e96e..e2e512b04393 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -608,17 +608,17 @@ class InitializeVirtualDesktopManagerTask : public Task {
   }
 #endif
 
-  virtual bool Run() override {
+  virtual TaskResult Run() override {
     RefPtr<IVirtualDesktopManager> desktopManager;
     HRESULT hr = ::CoCreateInstance(
         CLSID_VirtualDesktopManager, NULL, CLSCTX_INPROC_SERVER,
         __uuidof(IVirtualDesktopManager), getter_AddRefs(desktopManager));
     if (FAILED(hr)) {
-      return true;
+      return TaskResult::Complete;
     }
 
     gVirtualDesktopManager = desktopManager;
-    return true;
+    return TaskResult::Complete;
   }
 };
 
diff --git a/xpcom/threads/IdleTaskRunner.cpp b/xpcom/threads/IdleTaskRunner.cpp
index 2a61877fa050..d1a571d089a7 100644
--- a/xpcom/threads/IdleTaskRunner.cpp
+++ b/xpcom/threads/IdleTaskRunner.cpp
@@ -36,7 +36,7 @@ class IdleTaskRunnerTask : public Task {
     SetManager(TaskController::Get()->GetIdleTaskManager());
   }
 
-  bool Run() override {
+  TaskResult Run() override {
     if (mRunner) {
       // IdleTaskRunner::Run can actually trigger the destruction of the
       // IdleTaskRunner. Make sure it doesn't get destroyed before the method
@@ -44,7 +44,7 @@ class IdleTaskRunnerTask : public Task {
       RefPtr<IdleTaskRunner> runner(mRunner);
       runner->Run();
     }
-    return true;
+    return TaskResult::Complete;
   }
 
   void SetIdleDeadline(TimeStamp aDeadline) override {
diff --git a/xpcom/threads/TaskController.cpp b/xpcom/threads/TaskController.cpp
index c617f43217ed..0bf7d3160a4a 100644
--- a/xpcom/threads/TaskController.cpp
+++ b/xpcom/threads/TaskController.cpp
@@ -344,7 +344,7 @@ void TaskController::RunPoolThread() {
           MutexAutoUnlock unlock(mGraphMutex);
           lastTask = nullptr;
           AUTO_PROFILE_FOLLOWING_TASK(task);
-          taskCompleted = task->Run();
+          taskCompleted = task->Run() == Task::TaskResult::Complete;
           ranTask = true;
         }
 
@@ -545,10 +545,10 @@ class RunnableTask : public Task {
                Kind aKind)
       : Task(aKind, aPriority), mRunnable(aRunnable) {}
 
-  virtual bool Run() override {
+  virtual TaskResult Run() override {
     mRunnable->Run();
     mRunnable = nullptr;
-    return true;
+    return TaskResult::Complete;
   }
 
   void SetIdleDeadline(TimeStamp aDeadline) override {
@@ -873,7 +873,7 @@ bool TaskController::DoExecuteNextTaskOnlyMainThreadInternal(
           AutoSetMainThreadRunnableName nameGuard(name);
 #endif
           AUTO_PROFILE_FOLLOWING_TASK(task);
-          result = task->Run();
+          result = task->Run() == Task::TaskResult::Complete;
         }
 
         // Task itself should keep manager alive.
diff --git a/xpcom/threads/TaskController.h b/xpcom/threads/TaskController.h
index 5293604898bb..f51e61f4cd65 100644
--- a/xpcom/threads/TaskController.h
+++ b/xpcom/threads/TaskController.h
@@ -203,9 +203,14 @@ class Task {
 
   friend class TaskController;
 
-  // When this returns false, the task is considered incomplete and will be
-  // rescheduled at the current 'mPriority' level.
-  virtual bool Run() = 0;
+  enum class TaskResult {
+    Complete,
+    Incomplete,
+  };
+
+  // When this returns TaskResult::Incomplete, it will be rescheduled at the
+  // current 'mPriority' level.
+  virtual TaskResult Run() = 0;
 
  private:
   Task* GetHighestPriorityDependency();