Oilpan: fix build after r183834.

Source/web/tests/WebFrameTest.cpp

Index: Source/web/tests/WebFrameTest.cpp
diff --git a/Source/web/tests/WebFrameTest.cpp b/Source/web/tests/WebFrameTest.cpp
index 87d74a5f2fb5832e82e3a9889e394f5c1f40a29b..ff83e838edc7edd9794e34cf0e2496a828d03e3a 100644
--- a/Source/web/tests/WebFrameTest.cpp
+++ b/Source/web/tests/WebFrameTest.cpp
@@ -6519,7 +6519,7 @@ TEST_F(WebFrameTest, EmbedderTriggeredDetachWithRemoteMainFrame)
     WebLocalFrame* childFrame = view->mainFrame()->toWebRemoteFrame()->createLocalChild("", &childFrameClient);
 
     // Purposely keep the LocalFrame alive so it's the last thing to be destroyed.
-    RefPtr<Frame> childCoreFrame = toCoreFrame(childFrame);
+    RefPtrWillBePersistent<Frame> childCoreFrame = toCoreFrame(childFrame);

[dcheng, 2014/10/16 21:25:42]

Why not RefPtrWillBeRaw? This is a stack pointer.

[haraken, 2014/10/16 23:19:10]

In this case RefPtrWillBeRawPtr is fine, but we prefer using
RefPtrWillBePersistent in tests because we sometimes have the following code:

RefPtrWillBePersistent<X> x = ...;
Heap::collectAllGarbage();  // Run a precise GC (which assumes that there is no
stack pointer) to collect all objects reliably.
...;  // Test that some object is gone.

     view->close();
     childCoreFrame.clear();
 }