PlzNavigate: properly execute BeforeUnload on renderer initiated navigations

third_party/WebKit/public/web/WebLocalFrame.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebLocalFrame_h
 #define WebLocalFrame_h
 
 #include "WebFrame.h"
 #include "WebFrameLoadType.h"
 
@@ skipping 68 matching lines @@
     // optionally wrapping around.
     virtual WebLocalFrame* traversePreviousLocal(bool wrap) const = 0;
     virtual WebLocalFrame* traverseNextLocal(bool wrap) const = 0;
 
     // Navigation Ping --------------------------------------------------------
 
     virtual void sendPings(const WebURL& destinationURL) = 0;
 
     // Navigation ----------------------------------------------------------
 
+    enum class BeforeUnloadReturnValue {
+        Proceed,
+        DontProceed,
+        FrameDestroyed,
+    };
+
+    // Runs beforeunload handlers for this frame and updates |proceed| with the
+    // value returned by handlers. Returns false if the execution of
+    // BeforeUnload led to the destruction of the frame, true otherwise.

[dcheng, 2016/05/03 21:34:30]

Also, this comment should be updated.

[clamy, 2016/05/04 13:50:15]

Done.

+    virtual BeforeUnloadReturnValue dispatchBeforeUnloadEvent(bool isReload) = 0;
+
     // Returns a WebURLRequest corresponding to the load of the WebHistoryItem.
     virtual WebURLRequest requestFromHistoryItem(const WebHistoryItem&, WebCachePolicy) const = 0;
 
     // Returns a WebURLRequest corresponding to the reload of the current
     // HistoryItem.
     virtual WebURLRequest requestForReload(WebFrameLoadType,
         const WebURL& overrideURL = WebURL()) const = 0;
 
     // Load the given URL. For history navigations, a valid WebHistoryItem
     // should be given, as well as a WebHistoryLoadType.
@@ skipping 229 matching lines @@
     // to call these on a WebLocalFrame.
     bool isWebLocalFrame() const override = 0;
     WebLocalFrame* toWebLocalFrame() override = 0;
     bool isWebRemoteFrame() const override = 0;
     WebRemoteFrame* toWebRemoteFrame() override = 0;
 };
 
 } // namespace blink
 
 #endif // WebLocalFrame_h