Pausable Object Cleanup - PausableTask

Make PausableTask not inherit PausableTimer. There is no need
to schedule a timer since the kJavascriptTimer task queue already
is pausable. This class has no real user yet; Devlin claims that the
extension code will be using it soon.

BUG=907125

Change-Id: I270ef5d8e7f67c32d2377d8f8785ec56e941c204
Reviewed-on: https://chromium-review.googlesource.com/c/1378233Reviewed-by: Alexander Timin <altimin@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622083}

third_party/blink/renderer/core/exported/web_frame_test.cc

@@ -638,23 +638,22 @@ TEST_F(WebFrameTest, CallingPostPausableTaskWhilePaused)
   ScriptState::Scope scope(ToScriptStateForMainWorld(main_frame->GetFrame()));
 
   // Suspend scheduled tasks so the script doesn't run.
-  main_frame->GetFrame()->GetDocument()->PauseScheduledTasks();
+  web_view_helper.GetWebView()->GetPage()->SetPaused(true);
 
   ScriptNotPausedCallbackHelper callback_helper;
   main_frame->PostPausableTask(callback_helper.GetCallback());
   RunPendingTasks();
   EXPECT_FALSE(callback_helper.result());
 
-  main_frame->GetFrame()->GetDocument()->UnpauseScheduledTasks();
+  web_view_helper.GetWebView()->GetPage()->SetPaused(false);
   RunPendingTasks();
   ASSERT_TRUE(callback_helper.result());
   EXPECT_EQ(WebLocalFrame::PausableTaskResult::kReady,
             *callback_helper.result());
 }
 
-TEST_F(WebFrameTest, CallingPostPausableTaskAndNavigating) {
+TEST_F(WebFrameTest, CallingPostPausableTaskAndDestroying) {
   RegisterMockedHttpURLLoad("foo.html");
-  RegisterMockedHttpURLLoad("bar.html");
 
   frame_test_helpers::WebViewHelper web_view_helper;
   web_view_helper.InitializeAndLoad(base_url_ + "foo.html");
@@ -663,17 +662,14 @@ TEST_F(WebFrameTest, CallingPostPausableTaskAndNavigating) {
   ScriptState::Scope scope(ToScriptStateForMainWorld(main_frame->GetFrame()));
 
   // Suspend scheduled tasks so the script doesn't run.
-  main_frame->GetFrame()->GetDocument()->PauseScheduledTasks();
+  web_view_helper.GetWebView()->GetPage()->SetPaused(true);
 
   ScriptNotPausedCallbackHelper callback_helper;
   main_frame->PostPausableTask(callback_helper.GetCallback());
   RunPendingTasks();
   EXPECT_FALSE(callback_helper.result());
 
-  // If the frame navigates, pending scripts should be removed, but the callback
-  // should always be ran.
-  frame_test_helpers::LoadFrame(web_view_helper.GetWebView()->MainFrameImpl(),
-                                base_url_ + "bar.html");
+  web_view_helper.Reset();
   ASSERT_TRUE(callback_helper.result());
   EXPECT_EQ(WebLocalFrame::PausableTaskResult::kContextInvalidOrDestroyed,
             *callback_helper.result());

third_party/blink/renderer/core/frame/pausable_task.cc

@@ -6,6 +6,7 @@
 
 #include "base/location.h"
 #include "third_party/blink/renderer/core/dom/document.h"
+#include "third_party/blink/renderer/platform/wtf/functional.h"
 
 namespace blink {
 
@@ -25,7 +26,6 @@ void PausableTask::Post(ExecutionContext* context,
 }
 
 void PausableTask::ContextDestroyed(ExecutionContext* destroyed_context) {
-  PausableTimer::ContextDestroyed(destroyed_context);
   DCHECK(callback_);
 
   Dispose();
@@ -34,7 +34,7 @@ void PausableTask::ContextDestroyed(ExecutionContext* destroyed_context) {
       WebLocalFrame::PausableTaskResult::kContextInvalidOrDestroyed);
 }
 
-void PausableTask::Fired() {
+void PausableTask::Run() {
   CHECK(!GetExecutionContext()->IsContextDestroyed());
   DCHECK(!GetExecutionContext()->IsContextPaused());
   DCHECK(callback_);
@@ -50,23 +50,23 @@ void PausableTask::Fired() {
 
 PausableTask::PausableTask(ExecutionContext* context,
                            WebLocalFrame::PausableTaskCallback callback)
-    : PausableTimer(context, TaskType::kJavascriptTimer),
+    : ContextLifecycleObserver(context),
       callback_(std::move(callback)),
       keep_alive_(this) {
   DCHECK(callback_);
   DCHECK(context);
   DCHECK(!context->IsContextDestroyed());
   DCHECK(context->IsContextPaused());
-
-  StartOneShot(TimeDelta(), FROM_HERE);
-  PauseIfNeeded();
+  task_handle_ = PostCancellableTask(
+      *context->GetTaskRunner(TaskType::kInternalDefault), FROM_HERE,
+      WTF::Bind(&PausableTask::Run, WrapPersistent(this)));
 }
 
 void PausableTask::Dispose() {
   // Remove object as a ContextLifecycleObserver.
-  PausableObject::ClearContext();
+  ContextLifecycleObserver::ClearContext();
   keep_alive_.Clear();
-  Stop();
+  task_handle_.Cancel();
 }
 
 }  // namespace blink

third_party/blink/renderer/core/frame/pausable_task.h

@@ -9,8 +9,9 @@
 
 #include "third_party/blink/public/web/web_local_frame.h"
 #include "third_party/blink/renderer/core/core_export.h"
-#include "third_party/blink/renderer/core/frame/pausable_timer.h"
+#include "third_party/blink/renderer/core/dom/context_lifecycle_observer.h"
 #include "third_party/blink/renderer/platform/heap/self_keep_alive.h"
+#include "third_party/blink/renderer/platform/scheduler/public/post_cancellable_task.h"
 
 namespace blink {
 
@@ -19,13 +20,13 @@ namespace blink {
 // invalidated.
 class CORE_EXPORT PausableTask final
     : public GarbageCollectedFinalized<PausableTask>,
-      public PausableTimer {
+      public ContextLifecycleObserver {
   USING_GARBAGE_COLLECTED_MIXIN(PausableTask);
 
  public:
   // Note: This asserts that the context is currently suspended.
   PausableTask(ExecutionContext*, WebLocalFrame::PausableTaskCallback);
-  ~PausableTask() override;
+  virtual ~PausableTask();
 
   // Checks if the context is paused, and, if not, executes the callback
   // immediately. Otherwise constructs a PausableTask that will run the
@@ -34,12 +35,13 @@ class CORE_EXPORT PausableTask final
 
   // PausableTimer:
   void ContextDestroyed(ExecutionContext*) override;
-  void Fired() override;
 
  private:
+  void Run();
   void Dispose();
 
   WebLocalFrame::PausableTaskCallback callback_;
+  TaskHandle task_handle_;
 
   SelfKeepAlive<PausableTask> keep_alive_;
 };