Worker: Introduce per-global-scope task scheduler

third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp

 // Copyright 2016 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 "core/dom/TaskRunnerHelper.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/LocalFrame.h"
+#include "core/workers/WorkerOrWorkletGlobalScope.h"
+#include "core/workers/WorkerThread.h"
 #include "platform/WebFrameScheduler.h"
 #include "platform/WebTaskRunner.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebThread.h"
 
 namespace blink {
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type, LocalFrame* frame) {
   // TODO(haraken): Optimize the mapping from TaskTypes to task runners.
   switch (type) {
@@ skipping 37 matching lines @@
   NOTREACHED();
   return nullptr;
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type, Document* document) {
   return Get(type, document ? document->GetFrame() : nullptr);
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(
     TaskType type,
-    ExecutionContext* execution_context) {
-  return Get(type, execution_context && execution_context->IsDocument()
-                       ? static_cast<Document*>(execution_context)
-                       : nullptr);
+    ExecutionContext* executionContext) {
+  if (!executionContext)
+    return Get(type, ToDocument(executionContext));

[haraken, 2017/04/13 07:03:36]

Can we simply pass nullptr?

[nhiroki, 2017/04/13 08:23:50]

Hmmm... the clang compiler complains about the usage like this:

../../third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp:71:22: error: call
to 'ToDocument' is ambiguous
    return Get(type, ToDocument(nullptr));
                     ^~~~~~~~~~

Also, we cannot pass only "nullptr" because Get() is overloaded:

../../third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp:71:12: error: call
to 'Get' is ambiguous
    return Get(type, nullptr);

+  if (executionContext->IsDocument())
+    return Get(type, ToDocument(executionContext));
+  if (executionContext->IsWorkerOrWorkletGlobalScope())
+    return Get(type, ToWorkerOrWorkletGlobalScope(executionContext));
+  executionContext = nullptr;
+  return Get(type, ToDocument(executionContext));

[haraken, 2017/04/13 07:03:36]

Ditto.

 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type,
                                             ScriptState* script_state) {
   return Get(type,
              script_state ? ExecutionContext::From(script_state) : nullptr);
 }
 
+RefPtr<WebTaskRunner> TaskRunnerHelper::Get(
+    TaskType type,
+    WorkerOrWorkletGlobalScope* global_scope) {
+  DCHECK(global_scope);
+  // TODO(nhiroki): Add |DCHECK(global_scope->IsContextThread())| here after
+  // https://crbug.com/694925 is fixed.
+  return Get(type, global_scope->GetThread());
+}
+
+RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type,
+                                            WorkerThread* worker_thread) {
+  switch (type) {
+    case TaskType::kDOMManipulation:
+    case TaskType::kUserInteraction:
+    case TaskType::kNetworking:
+    case TaskType::kHistoryTraversal:
+    case TaskType::kEmbed:
+    case TaskType::kMediaElementEvent:
+    case TaskType::kCanvasBlobSerialization:
+    case TaskType::kMicrotask:
+    case TaskType::kTimer:
+    case TaskType::kRemoteEvent:
+    case TaskType::kWebSocket:
+    case TaskType::kPostedMessage:
+    case TaskType::kUnshippedPortMessage:
+    case TaskType::kFileReading:
+    case TaskType::kDatabaseAccess:
+    case TaskType::kPresentation:
+    case TaskType::kSensor:
+    case TaskType::kPerformanceTimeline:
+    case TaskType::kWebGL:
+    case TaskType::kMiscPlatformAPI:
+    case TaskType::kUnspecedTimer:
+    case TaskType::kUnspecedLoading:
+    case TaskType::kUnthrottled:
+      // UnthrottledTaskRunner is generally discouraged in future.
+      // TODO(nhiroki): Identify which tasks should be throttled and move them
+      // into other task runners. See also comments in Get(LocalFrame).
+      return worker_thread->GetGlobalScopeScheduler()->UnthrottledTaskRunner();
+  }
+  NOTREACHED();
+  return nullptr;
+}
+
 }  // namespace blink