Threading: Add thread checks in TaskRunnerHelper

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

Index: third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
diff --git a/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp b/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
index 631c5de8c0ec7a26c67b96aea14956e1c38bf507..afed2a87eab6e828831f3a4f4c1824631bd61046 100644
--- a/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
+++ b/third_party/WebKit/Source/core/dom/TaskRunnerHelper.cpp
@@ -17,6 +17,7 @@
 namespace blink {
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type, LocalFrame* frame) {
+  DCHECK(WTF::IsMainThread());
   // TODO(haraken): Optimize the mapping from TaskTypes to task runners.
   switch (type) {
     case TaskType::kTimer:
@@ -61,20 +62,18 @@ RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type, LocalFrame* frame) {
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type, Document* document) {
+  DCHECK(!document || document->IsContextThread());
   return Get(type, document ? document->GetFrame() : nullptr);
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(
     TaskType type,
-    ExecutionContext* executionContext) {
-  if (!executionContext)
-    return Get(type, ToDocument(executionContext));
-  if (executionContext->IsDocument())
-    return Get(type, ToDocument(executionContext));
-  if (executionContext->IsWorkerOrWorkletGlobalScope())
-    return Get(type, ToWorkerOrWorkletGlobalScope(executionContext));
-  executionContext = nullptr;
-  return Get(type, ToDocument(executionContext));
+    ExecutionContext* execution_context) {
+  DCHECK(!execution_context || execution_context->IsContextThread());
+  if (!execution_context || execution_context->IsDocument())
+    return Get(type, ToDocument(execution_context));
+  DCHECK(execution_context->IsWorkerOrWorkletGlobalScope());
+  return Get(type, ToWorkerOrWorkletGlobalScope(execution_context));
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type,