wpt: Fix the test of history.state === popStateEvent.state

Firefox, Safari, and Chrome agree the behavior of
    history.state === popStateEvent.state
so update the test case accordingly.

IIUC, HTML also requires this behavior.
https://html.spec.whatwg.org/C/#history-traversal:dom-history-state
step 13. Set history.state to state.
step 16.1. If state changed is true, then fire an event
  named popstate at the Document object's relevant global
  object, using PopStateEvent, with the state attribute
  initialized to state.
where |state| is the result of StructuredDeserialize, so it's
expected that history.state === popStateEvent.state.

Bug: 1070938
Change-Id: I161e415ce986be56031080e1538a0d4ac4fbf133
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2147169Reviewed-by: Domenic Denicola <domenic@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759269}

third_party/blink/web_tests/external/wpt/html/browsers/history/the-history-interface/001-expected.txt

@@ -36,7 +36,7 @@ PASS state data should cope with circular object references
 PASS state data should be a clone of the original object, not a reference to it
 PASS history.state should also reference a clone of the original object (2)
 PASS history.state should be a clone of the original object, not a reference to it (2)
-FAIL history.state should be a separate clone of the object, not a reference to the object passed to the event handler assert_false: expected false got true
+PASS history.state should be identical to the object passed to the event handler unless history.state is updated
 PASS pushState should not actually load the new URL
 PASS reloading a pushed state should actually load the new URL
 Harness: the test ran to completion.

third_party/blink/web_tests/external/wpt/html/browsers/history/the-history-interface/001.html

@@ -274,8 +274,8 @@ function reportload() {
             assert_false( cloneobj === iframe.contentWindow.history.state );
         }, 'history.state should be a clone of the original object, not a reference to it (2)');
         test(function () {
-            assert_false( iframe.contentWindow.history.state === ev.state );
-        }, 'history.state should be a separate clone of the object, not a reference to the object passed to the event handler');
+            assert_true( iframe.contentWindow.history.state === ev.state );
+        }, 'history.state should be identical to the object passed to the event handler unless history.state is updated');
         try {
             iframe.contentWindow.persistval = true;
             iframe.contentWindow.history.pushState('','', location.href.replace(/\/[^\/]*$/,'/blank3.html') );

third_party/blink/web_tests/external/wpt/html/browsers/history/the-history-interface/002-expected.txt

-This is a testharness.js-based test.
-PASS history.length should update when loading pages in an iframe
-PASS history.length should update when setting location.hash
-PASS history.replaceState must exist
-PASS history.replaceState must exist within iframes
-PASS initial history.state should be null
-PASS history.length should not update when replacing a state with no URL
-PASS history.state should update after a state is pushed
-PASS hash should not change when replaceState is called without a URL
-PASS history.length should not update when replacing a state with a URL
-PASS hash should change when replaceState is called with a URL
-PASS replaceState must replace the existing state and not add an extra one
-PASS replaceState must replace the existing state without altering the forward history
-PASS replaceState must not be allowed to create invalid URLs
-PASS replaceState must not be allowed to create cross-origin URLs
-PASS replaceState must not be allowed to create cross-origin URLs (about:blank)
-PASS replaceState must not be allowed to create cross-origin URLs (data:URI)
-PASS security errors are expected to be thrown in the context of the document that owns the history object
-PASS replaceState must be able to set location.pathname
-PASS replaceState must be able to set absolute URLs to the same host
-PASS replaceState must not remove any tasks queued by the history traversal task source
-PASS .go must queue a task with the history traversal task source (run asynchronously)
-PASS replaceState must not fire hashchange events
-PASS replaceState must not be able to use a function as data
-PASS replaceState must not be able to use a DOM node as data
-PASS replaceState must be able to use an error object as data
-PASS security errors are expected to be thrown in the context of the document that owns the history object (2)
-PASS replaceState must be able to make structured clones of complex objects
-PASS history.state should also reference a clone of the original object
-PASS history.state should be a clone of the original object, not a reference to it
-PASS popstate event should fire when navigation occurs
-PASS popstate event should pass the state data
-PASS state data should cope with circular object references
-PASS state data should be a clone of the original object, not a reference to it
-PASS history.state should also reference a clone of the original object (2)
-PASS history.state should be a clone of the original object, not a reference to it (2)
-FAIL history.state should be a separate clone of the object, not a reference to the object passed to the event handler assert_false: expected false got true
-PASS replaceState should not actually load the new URL
-PASS reloading a replaced state should actually load the new URL
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/html/browsers/history/the-history-interface/002.html

@@ -249,8 +249,8 @@ function reportload() {
             assert_false( cloneobj === iframe.contentWindow.history.state );
         }, 'history.state should be a clone of the original object, not a reference to it (2)');
         test(function () {
-            assert_false( iframe.contentWindow.history.state === ev.state );
-        }, 'history.state should be a separate clone of the object, not a reference to the object passed to the event handler');
+            assert_true( iframe.contentWindow.history.state === ev.state );
+        }, 'history.state should be identical to the object passed to the event handler unless history.state is updated');
         try {
             iframe.contentWindow.persistval = true;
             iframe.contentWindow.history.replaceState('','', location.href.replace(/\/[^\/]*$/,'/blank3.html') );