WorkerLoaderProxy: stop accessing cross-thread execution context

third_party/WebKit/Source/core/workers/WorkerLoaderProxy.cpp

Index: third_party/WebKit/Source/core/workers/WorkerLoaderProxy.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerLoaderProxy.cpp b/third_party/WebKit/Source/core/workers/WorkerLoaderProxy.cpp
index dd8655f571c7bfb72956c3472964114519b8b6ad..8a705a837d15e3aad317bff592a9c06323f5f729 100644
--- a/third_party/WebKit/Source/core/workers/WorkerLoaderProxy.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerLoaderProxy.cpp
@@ -4,7 +4,7 @@
 
 #include "core/workers/WorkerLoaderProxy.h"
 
-#include "core/dom/ExecutionContextTask.h"
+#include "core/dom/ExecutionContext.h"
 
 namespace blink {
 
@@ -26,7 +26,7 @@ void WorkerLoaderProxy::detachProvider(
 
 void WorkerLoaderProxy::postTaskToLoader(
     const WebTraceLocation& location,
-    std::unique_ptr<ExecutionContextTask> task) {
+    std::unique_ptr<WTF::CrossThreadClosure> task) {
   MutexLocker locker(m_lock);
   DCHECK(!isMainThread());
   if (!m_loaderProxyProvider)
@@ -44,4 +44,12 @@ void WorkerLoaderProxy::postTaskToWorkerGlobalScope(
   m_loaderProxyProvider->postTaskToWorkerGlobalScope(location, std::move(task));
 }
 
+ExecutionContext* WorkerLoaderProxy::getLoaderExecutionContext() {
+  MutexLocker locker(m_lock);

[haraken, 2017/02/23 09:11:54]

Would you help me understand why we need this lock? I was assuming that
getLoaderExecutionContext is accessed only by the main thread.

[kinuko, 2017/02/23 09:25:18]

This was to protect m_loaderProxyProvider access. But looking into the calling
convention detachProvider can be only called on the main thread too, so looks
like we can remove this (and the one in postTaskToWorkerGlobalScope).  Done.

+  if (!m_loaderProxyProvider)
+    return nullptr;
+  DCHECK(m_loaderProxyProvider->getLoaderExecutionContext()->isContextThread());
+  return m_loaderProxyProvider->getLoaderExecutionContext();
+}
+
 }  // namespace blink