PlzNavigate: properly execute BeforeUnload on renderer initiated navigations

third_party/WebKit/LayoutTests/FlagExpectations/enable-browser-side-navigation

 # Last updated: 2016-24-2 based on results from the trybot
 # linux_chromium_browser_side_navigation_rel
 
 # Run 1
 # Expected to fail, but passed: (6)
   editing/pasteboard/4944770-2.html
   fast/css/absolute-inline-alignment.html
   fast/dom/shadow/scoped-events-by-ua-stopped.html
   fast/encoding/invalid-UTF-8.html
   fast/forms/month/month-appearance-l10n.html
@@ skipping 17 matching lines @@
   imported/web-platform-tests/mediacapture-streams/obtaining-local-multimedia-content/navigatorusermedia/getusermedia-optional-constraint.html
   virtual/rootlayerscrolls/fast/scrolling/fractional-scroll-offset-fixed-position-non-composited.html
   virtual/rootlayerscrolls/scrollbars/custom-scrollbar-changing-style.html
 
 # Expected to timeout, but passed: (4)
   inspector/elements/edit/edit-dom-actions.html
 
 # Regressions: Unexpected crashes (53)
   dom/xhtml/level2/html/HTMLIFrameElement11.xhtml [ Crash Timeout ]
   editing/execCommand/apply-style-command-crash.html [ Crash ]
-  editing/pasteboard/file-drag-to-editable.html [ Crash Failure ]
   editing/style/apply-style-crash.html [ Crash ]
   fast/css/acid2-pixel.html [ Crash Timeout ]
   fast/css/acid2.html [ Crash Timeout ]
   fast/dom/HTMLObjectElement/children-changed.html [ Crash Timeout ]
   fast/dom/HTMLScriptElement/script-element-moved-to-detached-document-crash.html [ Crash Timeout ]
   fast/dom/Range/acid3-surround-contents.html [ Crash Timeout ]
   fast/dom/Window/window-resize-and-move-sub-frame.html [ Crash Timeout ]
   fast/dom/exception-no-frame-timeout-crash.html [ Crash Timeout ]
   fast/dom/location-new-window-no-crash.html [ Crash ]
   http/tests/appcache/main-resource-hash.html [ Crash Timeout ]
   http/tests/appcache/main-resource-redirect.html [ Crash Timeout ]
   http/tests/appcache/non-html.xhtml [ Crash Timeout ]
   http/tests/appcache/offline-access.html [ Crash Timeout ]
   http/tests/cache/iframe-304-crash.html [ Crash Failure ]
   http/tests/history/cross-origin-redirect-on-back.html [ Crash ]
   http/tests/history/post-replace-state-reload.html [ Crash Failure ]
   http/tests/navigation/location-reload-after-post.php [ Crash Failure ]
-  virtual/pointerevent/fast/events/before-unload-return-bad-value.html [ Crash Failure ]
-  virtual/pointerevent/fast/events/before-unload-return-value-from-listener.html [ Crash Failure ]
-  virtual/pointerevent/fast/events/before-unload-returnValue.html [ Crash Failure ]
-  virtual/pointerevent/fast/events/drop-handler-should-not-stop-navigate.html [ Crash Failure ]
   virtual/pointerevent/fast/events/focusingUnloadedFrame.html [ Crash Timeout ]
   virtual/pointerevent/fast/events/onload-webkit-before-webcore.html [ Crash Timeout ]
   virtual/pointerevent/fast/events/onloadFrameCrash.html [ Crash Timeout ]
-  virtual/pointerevent/fast/events/only-valid-drop-targets-receive-file-drop.html [ Crash Failure ]
-  virtual/trustedeventsdefaultaction/fast/events/before-unload-return-bad-value.html [ Crash Failure ]
-  virtual/trustedeventsdefaultaction/fast/events/before-unload-return-value-from-listener.html [ Crash Failure ]
-  virtual/trustedeventsdefaultaction/fast/events/before-unload-returnValue.html [ Crash Failure ]
-  virtual/trustedeventsdefaultaction/fast/events/drop-handler-should-not-stop-navigate.html [ Crash Failure ]
   virtual/trustedeventsdefaultaction/fast/events/focusingUnloadedFrame.html [ Crash Timeout ]
   virtual/trustedeventsdefaultaction/fast/events/onload-webkit-before-webcore.html [ Crash Timeout ]
   virtual/trustedeventsdefaultaction/fast/events/onloadFrameCrash.html [ Crash Timeout ]
   virtual/trustedeventsdefaultaction/fast/events/only-valid-drop-targets-receive-file-drop.html [ Crash Failure ]
 
 # Regressions: Unexpected missing results (1)
   http/tests/security/upgrade-insecure-requests/https-header-top-level.html [ Missing ]
 
 # Regressions: Unexpected text-only failures (69)
   fast/dom/frame-loading-via-document-write.html [ Failure ]
@@ skipping 139 matching lines @@
   http/tests/w3c/webperf/submission/Google/resource-timing/html/test_resource_redirects.html [ Failure ]
   imported/web-platform-tests/html/browsers/history/the-history-interface/004.html [ Failure ]
   imported/web-platform-tests/html/browsers/history/the-location-interface/security_location_0.sub.htm [ Failure ]
   inspector-protocol/page/frameAttachedDetached.html [ Failure ]
   inspector-protocol/page/frameStartedLoading.html [ Failure ]
 
 # Regressions: Unexpected image-only failures (1)
   svg/custom/anchor-on-use.svg [ Failure ]
 
 # Regressions: Unexpected crashes (55)
-  fast/events/before-unload-return-bad-value.html [ Crash Failure ]
-  fast/events/before-unload-return-value-from-listener.html [ Crash Failure ]
-  fast/events/before-unload-returnValue.html [ Crash Failure ]
-  fast/events/drop-handler-should-not-stop-navigate.html [ Crash Failure ]
   fast/events/focusingUnloadedFrame.html [ Crash Timeout ]
   fast/events/onload-webkit-before-webcore.html [ Crash Timeout ]
   fast/events/onloadFrameCrash.html [ Crash Timeout ]
-  fast/events/only-valid-drop-targets-receive-file-drop.html [ Crash Failure ]
   fast/frames/empty-frame-document.html [ Crash Timeout ]
   fast/frames/iframe-plugin-load-remove-document-crash.html [ Crash ]
   fast/innerHTML/innerHTML-iframe.html [ Crash Timeout ]
   fast/loader/iframe-crash-on-missing-image.xhtml [ Crash Timeout ]
-  fast/loader/recursive-before-unload-crash.html [ Crash Failure ]
   fast/loader/reload-zero-byte-plugin.html [ Crash ]
   fast/loader/stateobjects/pushstate-with-fragment-urls-and-hashchange.html [ Crash Timeout ]
   fast/overflow/overflow-height-float-not-removed-crash.html [ Crash Timeout ]
   fast/overflow/overflow-height-float-not-removed-crash2.html [ Crash Timeout ]
   fast/overflow/overflow-height-float-not-removed-crash3.html [ Crash Timeout ]
   fast/parser/empty-text-resource.html [ Crash Timeout ]
   fast/table/crash-splitColumn-2.html [ Crash Timeout ]
   fast/table/giantCellspacing.html [ Crash Timeout ]
   fast/xmlhttprequest/null-document-xmlhttprequest-open.html [ Crash Timeout ]
   http/tests/loading/bad-server-subframe.html [ Crash Timeout ]
@@ skipping 103 matching lines @@
 # Regressions: Unexpected text-only failures (3)
   imported/web-platform-tests/web-animations/keyframe-effect/getComputedTiming-currentIteration.html [ Failure ]
   imported/web-platform-tests/web-animations/keyframe-effect/getComputedTiming-progress.html [ Failure ]
 
 # Update on 16-4-14
 
 # Regressions: Unexpected text-only failures (2)
   http/tests/security/mixedContent/insecure-prefetch-in-main-frame.html [ Failure ]
   imported/web-platform-tests/web-animations/animation-timeline/document-timeline.html [ Failure ]