Revert of Fix Blink commit type for subframes after initial about:blank load.

Source/core/loader/NavigationScheduler.cpp

Index: Source/core/loader/NavigationScheduler.cpp
diff --git a/Source/core/loader/NavigationScheduler.cpp b/Source/core/loader/NavigationScheduler.cpp
index bd3f2e8c223fbdf07050626f98390dee7434fdcf..2ac74b8ed38c84b0d4aca49c8d1f9eb81f40c468 100644
--- a/Source/core/loader/NavigationScheduler.cpp
+++ b/Source/core/loader/NavigationScheduler.cpp
@@ -292,6 +292,14 @@
     if (!UserGestureIndicator::processingUserGesture() && !targetFrame->document()->loadEventFinished())
         return true;
 
+    // From the HTML5 spec for location.assign():
+    //  "If the browsing context's session history contains only one Document,
+    //   and that was the about:blank Document created when the browsing context
+    //   was created, then the navigation must be done with replacement enabled."
+    if (!targetFrame->loader().stateMachine()->committedMultipleRealLoads()
+        && equalIgnoringCase(targetFrame->document()->url(), blankURL()))
+        return true;
+
     // Navigation of a subframe during loading of an ancestor frame does not create a new back/forward item.
     // The definition of "during load" is any time before all handlers for the load event have been run.
     // See https://bugs.webkit.org/show_bug.cgi?id=14957 for the original motivation for this.