Revert of Detach old frame on WebFrame::swap.

Source/web/WebFrame.cpp

Index: Source/web/WebFrame.cpp
diff --git a/Source/web/WebFrame.cpp b/Source/web/WebFrame.cpp
index 8bea271892dbd369fdb1b4bc8e2cf73815ff9ce1..b7504104a33a316fa96046dccffa5a74da7d4b35 100644
--- a/Source/web/WebFrame.cpp
+++ b/Source/web/WebFrame.cpp
@@ -39,26 +39,16 @@
 {
     using std::swap;
     RefPtrWillBeRawPtr<Frame> oldFrame = toCoreFrame(this);
-#if !ENABLE(OILPAN)
-    RefPtrWillBeRawPtr<WebLocalFrameImpl> protectWebLocalFrame = isWebLocalFrame() ? toWebLocalFrameImpl(this) : nullptr;
-    RefPtrWillBeRawPtr<WebRemoteFrameImpl> protectWebRemoteFrame = isWebRemoteFrame() ? toWebRemoteFrameImpl(this) : nullptr;
-#endif
-
-    // If the frame has been detached during detaching by any JS code, we should
-    // cancel the swap.
+
+    // All child frames must be detached first.
+    oldFrame->detachChildren();
+
+    // If the frame has been detached during detaching its children, return
+    // immediately.
     // FIXME: There is no unit test for this condition, so one needs to be
     // written.
-    if (!oldFrame->prepareForCommit())
+    if (!oldFrame->host())
         return false;
-
-    FrameOwner* owner = oldFrame->owner();
-    FrameHost* host = oldFrame->host();
-
-    // Frame::detach will call clearForClose(), we need to call
-    // clearForNavigate() before detaching.
-    oldFrame->prepareSwapFrom(oldFrame.get());
-
-    oldFrame->detach(FrameDetachType::Swap);
 
     if (m_parent) {
         if (m_parent->m_firstChild == this)
@@ -96,6 +86,8 @@
     // the type of the passed in WebFrame.
     // FIXME: This is a bit clunky; this results in pointless decrements and
     // increments of connected subframes.
+    FrameOwner* owner = oldFrame->owner();
+    oldFrame->disconnectOwnerElement();
     if (frame->isWebLocalFrame()) {
         LocalFrame& localFrame = *toWebLocalFrameImpl(frame)->frame();
         ASSERT(owner == localFrame.owner());
@@ -111,7 +103,7 @@
             localFrame.page()->setMainFrame(&localFrame);
         }
     } else {
-        toWebRemoteFrameImpl(frame)->initializeCoreFrame(host, owner, oldFrame->tree().name());
+        toWebRemoteFrameImpl(frame)->initializeCoreFrame(oldFrame->host(), owner, oldFrame->tree().name());
     }
     toCoreFrame(frame)->finishSwapFrom(oldFrame.get());
 
@@ -120,7 +112,7 @@
 
 void WebFrame::detach()
 {
-    toCoreFrame(this)->detach(FrameDetachType::Remove);
+    toCoreFrame(this)->detach();
 }
 
 WebSecurityOrigin WebFrame::securityOrigin() const