[oilpan]: Fix webkit unit tests for oilpan.

Source/web/tests/WebViewTest.cpp

Index: Source/web/tests/WebViewTest.cpp
diff --git a/Source/web/tests/WebViewTest.cpp b/Source/web/tests/WebViewTest.cpp
index 60a64287b59825d9f426122b721fd0f98052d5b6..1bded023019b6b04561d7f58e078d6f59a275b45 100644
--- a/Source/web/tests/WebViewTest.cpp
+++ b/Source/web/tests/WebViewTest.cpp
@@ -1809,7 +1809,7 @@ TEST_F(WebViewTest, DeleteElementWithRegisteredHandler)
     URLTestHelpers::registerMockedURLLoad(toKURL(url), "simple_div.html");
     WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(url, true);
 
-    WebCore::Document* document = webViewImpl->mainFrameImpl()->frame()->document();
+    RefPtrWillBePersistent<WebCore::Document> document = webViewImpl->mainFrameImpl()->frame()->document();

[jochen (gone - plz use gerrit), 2014/07/17 14:17:24]

why this change?

[wibling-chromium, 2014/07/17 14:18:51]

Because I am doing a GC with no pointers on stack which means any object on the
stack will not be traced. By putting the Document into a Persistent I am
guaranteed the registry is still around after my GC.

     WebCore::Element* div = document->getElementById("div");
     WebCore::EventHandlerRegistry& registry = document->frameHost()->eventHandlerRegistry();
 
@@ -1818,6 +1818,11 @@ TEST_F(WebViewTest, DeleteElementWithRegisteredHandler)
 
     WebCore::TrackExceptionState exceptionState;
     div->remove(exceptionState);
+#if ENABLE(OILPAN)
+    // For oilpan we have to force a GC to ensure the event handlers have been removed when
+    // checking below.
+    Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);

[haraken, 2014/07/17 14:32:28]

We prefer using Heap::collectAllGarbage() in tests.

[wibling-chromium, 2014/07/17 14:37:53]

Done.

+#endif
     EXPECT_FALSE(registry.hasEventHandlers(WebCore::EventHandlerRegistry::ScrollEvent));
 }