Detach all subframes before swapping a frame.

Source/web/tests/WebFrameTest.cpp

 /*
  * Copyright (C) 2010 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 6051 matching lines @@
     FrameTestHelpers::loadFrame(localFrame, m_baseURL + "subframe-hello.html");
     std::string content = localFrame->contentAsText(1024).utf8();
     EXPECT_EQ("hello", content);
 
     // Manually reset to break WebViewHelper's dependency on the stack allocated
     // TestWebFrameClient.
     reset();
     remoteFrame->close();
 }
 
+void swapAndVerifySubframeConsistency(const char* const message, WebFrame* oldFrame, WebFrame* newFrame)
+{
+    SCOPED_TRACE(message);
+
+    EXPECT_TRUE(oldFrame->firstChild());
+    oldFrame->swap(newFrame);
+
+    EXPECT_FALSE(newFrame->firstChild());
+    EXPECT_FALSE(newFrame->lastChild());
+}
+
+TEST_F(WebFrameSwapTest, SwapParentShouldDetachChildren)
+{
+    WebRemoteFrame* remoteFrame = WebRemoteFrame::create(0);
+    WebFrame* targetFrame = mainFrame()->firstChild()->nextSibling();
+    EXPECT_TRUE(targetFrame);
+    swapAndVerifySubframeConsistency("local->remote", targetFrame, remoteFrame);
+
+    targetFrame = mainFrame()->firstChild()->nextSibling();
+    EXPECT_TRUE(targetFrame);
+
+    // Create child frames in the target frame before testing the swap.
+    FrameTestHelpers::TestWebFrameClient remoteFrameClient;
+    remoteFrame->createRemoteChild("", &remoteFrameClient);
+
+    FrameTestHelpers::TestWebFrameClient client;
+    WebFrame* localFrame = WebLocalFrame::create(&client);
+    swapAndVerifySubframeConsistency("remote->local", targetFrame, localFrame);
+
+    // FIXME: This almost certainly fires more load events on the iframe element
+    // than it should.
+    // Finally, make sure an embedder triggered load in the local frame swapped
+    // back in works.
+    FrameTestHelpers::loadFrame(localFrame, m_baseURL + "subframe-hello.html");
+    std::string content = localFrame->contentAsText(1024).utf8();
+    EXPECT_EQ("hello", content);
+
+    // Manually reset to break WebViewHelper's dependency on the stack allocated
+    // TestWebFrameClient.
+    reset();
+    remoteFrame->close();
+}
+
 class MockDocumentThreadableLoaderClient : public DocumentThreadableLoaderClient {
 public:
     MockDocumentThreadableLoaderClient() : m_failed(false) { }
     virtual void didFail(const ResourceError&) OVERRIDE { m_failed = true;}
 
     void reset() { m_failed = false; }
     bool failed() { return m_failed; }
 
     bool m_failed;
 };
@@ skipping 91 matching lines @@
     EXPECT_EQ(1u, frameClient.navigationalDataReceivedCount());
 
     // Neither should a page reload.
     localFrame->reload();
     EXPECT_EQ(4u, frameClient.provisionalLoadCount());
     EXPECT_FALSE(frameClient.wasLastProvisionalLoadATransition());
     EXPECT_EQ(1u, frameClient.navigationalDataReceivedCount());
 }
 
 } // namespace