HTML Imports: Get rid of needsProcessOrStop() from dom/custom/

Source/core/dom/custom/CustomElementMicrotaskDispatcher.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/dom/custom/CustomElementMicrotaskDispatcher.h"
 
 #include "core/dom/Microtask.h"
+#include "core/dom/custom/CustomElementAsyncImportMicrotaskQueue.h"
 #include "core/dom/custom/CustomElementCallbackDispatcher.h"
 #include "core/dom/custom/CustomElementCallbackQueue.h"
 #include "core/dom/custom/CustomElementMicrotaskImportStep.h"
 #include "core/dom/custom/CustomElementMicrotaskQueue.h"
 #include "core/dom/custom/CustomElementScheduler.h"
 #include "core/html/imports/HTMLImportLoader.h"
 #include "wtf/MainThread.h"
 
 namespace WebCore {
 
 static const CustomElementCallbackQueue::ElementQueueId kMicrotaskQueueId = 0;
 
 CustomElementMicrotaskDispatcher::CustomElementMicrotaskDispatcher()
     : m_hasScheduledMicrotask(false)
     , m_phase(Quiescent)
     , m_resolutionAndImports(CustomElementMicrotaskQueue::create())
+    , m_asyncImports(CustomElementAsyncImportMicrotaskQueue::create())
 {
 }
 
+CustomElementMicrotaskDispatcher::~CustomElementMicrotaskDispatcher()
+{
+}
+
 CustomElementMicrotaskDispatcher& CustomElementMicrotaskDispatcher::instance()
 {
     DEFINE_STATIC_LOCAL(CustomElementMicrotaskDispatcher, instance, ());
     return instance;
 }
 
 void CustomElementMicrotaskDispatcher::enqueue(HTMLImportLoader* importLoader, PassOwnPtr<CustomElementMicrotaskStep> step)
 {
     ASSERT(m_phase == Quiescent || m_phase == DispatchingCallbacks);
     ensureMicrotaskScheduled();
     if (importLoader)
         importLoader->microtaskQueue()->enqueue(step);
     else
         m_resolutionAndImports->enqueue(step);
 }
 
 void CustomElementMicrotaskDispatcher::enqueue(CustomElementCallbackQueue* queue)
 {
     ASSERT(m_phase == Quiescent || m_phase == Resolving);
     ensureMicrotaskScheduled();
     queue->setOwner(kMicrotaskQueueId);
     m_elements.append(queue);
 }
 
+void CustomElementMicrotaskDispatcher::enqueueAsyncImportStep(PassOwnPtr<CustomElementMicrotaskImportStep> step)
+{
+    ASSERT(m_phase == Quiescent || m_phase == DispatchingCallbacks);

[dominicc (has gone to gerrit), 2014/05/25 23:55:10]

Can we refactor to eliminate the duplication of these two lines with
enqueue(HTMLImportLoader*, ...)?

I'm fine if you change the signature, calling of the other one to do it.

For example, I think whether an import is "sync" is already part of its public
API; can we keep the fact that CustomElementMicrotaskDispatcher has two separate
queues a private implementation detail of this class? (At least at the API
level; I understand that the order will change and the async ones will may go
later than they do today.)

[Hajime Morrita, 2014/05/27 21:12:47]

Done. Made some rearrangement around signature and also extracted the "ensure"
bit.

+    ensureMicrotaskScheduled();
+    m_asyncImports->enqueue(step);
+}
+
 void CustomElementMicrotaskDispatcher::importDidFinish(CustomElementMicrotaskImportStep* step)
 {
     ASSERT(m_phase == Quiescent || m_phase == DispatchingCallbacks);
     ensureMicrotaskScheduled();
 }
 
 void CustomElementMicrotaskDispatcher::ensureMicrotaskScheduled()
 {
     if (!m_hasScheduledMicrotask) {
         Microtask::enqueueMicrotask(WTF::bind(&dispatch));
@@ skipping 13 matching lines @@
     ASSERT(m_phase == Quiescent && m_hasScheduledMicrotask);
     m_hasScheduledMicrotask = false;
 
     // Finishing microtask work deletes all
     // CustomElementCallbackQueues. Being in a callback delivery scope
     // implies those queues could still be in use.
     ASSERT_WITH_SECURITY_IMPLICATION(!CustomElementCallbackDispatcher::inCallbackDeliveryScope());
 
     m_phase = Resolving;
     m_resolutionAndImports->dispatch();
+    if (m_resolutionAndImports->isEmpty())
+        m_asyncImports->dispatch();

[dominicc (has gone to gerrit), 2014/05/25 23:55:10]

Could we dispatch these anyway? WDYT?

[Hajime Morrita, 2014/05/27 21:12:47]

That makes some tests fail.
Async imports don't block followers, but they are blocked by imports that came
before.

[dominicc (has gone to gerrit), 2014/05/27 23:41:25]

I remembered this in the middle of the night last night. I like the behavior of
async imports going later like this, so this is nice as-is.

 
     m_phase = DispatchingCallbacks;
     for (Vector<CustomElementCallbackQueue*>::iterator it = m_elements.begin();it != m_elements.end(); ++it) {
         // Created callback may enqueue an attached callback.
         CustomElementCallbackDispatcher::CallbackDeliveryScope scope;
         (*it)->processInElementQueue(kMicrotaskQueueId);
     }
 
     m_elements.clear();
     CustomElementScheduler::microtaskDispatcherDidFinish();
     m_phase = Quiescent;
 }
 
 #if !defined(NDEBUG)
 void CustomElementMicrotaskDispatcher::show()
 {
     fprintf(stderr, "Dispatcher:\n");
-    m_resolutionAndImports->show(1);
+    fprintf(stderr, "  Sync:\n");
+    m_resolutionAndImports->show(3);
+    fprintf(stderr, "  Async:\n");
+    m_asyncImports->show(3);
+
 }
 #endif
 
 } // namespace WebCore
 
 #if !defined(NDEBUG)
 void showCEMD()
 {
     WebCore::CustomElementMicrotaskDispatcher::instance().show();
 }
 #endif