Add thread affinity and ASSERT() for same-thread restriction to WTF::Function

third_party/WebKit/Source/platform/Task.h

Index: third_party/WebKit/Source/platform/Task.h
diff --git a/third_party/WebKit/Source/platform/Task.h b/third_party/WebKit/Source/platform/Task.h
index 64b656c7374f14261d098c250be6bdc7c1f009db..e404408db018e93220302972fef2c06df968bac3 100644
--- a/third_party/WebKit/Source/platform/Task.h
+++ b/third_party/WebKit/Source/platform/Task.h
@@ -40,11 +40,34 @@
 
 namespace blink {
 
-class Task : public WebTaskRunner::Task {
-    USING_FAST_MALLOC(Task);
-    WTF_MAKE_NONCOPYABLE(Task);
+// Please use WTF::SameThreadClosure or WTF::CrossThreadClosure directly,
+// instead of wrapping them by blink::SameThreadTask/CrossThreadTask here.
+
+// TODO(hiroshige): Make these classes internal to
+// Source/platform/WebTaskRunner.cpp.
+class SameThreadTask : public WebTaskRunner::Task {
+    USING_FAST_MALLOC(SameThreadTask);
+    WTF_MAKE_NONCOPYABLE(SameThreadTask);
+public:
+    explicit SameThreadTask(PassOwnPtr<SameThreadClosure> closure)
+        : m_closure(std::move(closure))
+    {
+    }
+
+    void run() override
+    {
+        (*m_closure)();
+    }
+
+private:
+    OwnPtr<SameThreadClosure> m_closure;
+};
+
+class CrossThreadTask : public WebTaskRunner::Task {
+    USING_FAST_MALLOC(CrossThreadTask);
+    WTF_MAKE_NONCOPYABLE(CrossThreadTask);
 public:
-    explicit Task(PassOwnPtr<Closure> closure)
+    explicit CrossThreadTask(PassOwnPtr<CrossThreadClosure> closure)
         : m_closure(std::move(closure))
     {
     }
@@ -55,7 +78,7 @@ public:
     }
 
 private:
-    OwnPtr<Closure> m_closure;
+    OwnPtr<CrossThreadClosure> m_closure;
 };
 
 } // namespace blink