Expose base::Callback::IsCancelled via WTF::Function

third_party/WebKit/Source/wtf/FunctionalTest.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 571 matching lines @@
     EXPECT_LE((*bound2)(CountCopy()), 2); // Compiler is allowed to optimize one copy away if the argument is rvalue.
 }
 
 TEST(FunctionalTest, WeakPtr)
 {
     HasWeakPtrSupport obj;
     int counter = 0;
     std::unique_ptr<WTF::Closure> bound = WTF::bind(&HasWeakPtrSupport::increment, obj.createWeakPtr(), WTF::unretained(&counter));
 
     (*bound)();
+    EXPECT_FALSE(bound->isCancelled());
     EXPECT_EQ(1, counter);
 
     obj.revokeAll();
+    EXPECT_TRUE(bound->isCancelled());
     (*bound)();
     EXPECT_EQ(1, counter);
 }
 
 } // anonymous namespace
 
 } // namespace WTF