headless: Require the user to pass in an initial URL

headless/public/headless_web_contents.h

 // Copyright 2015 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 HEADLESS_PUBLIC_HEADLESS_WEB_CONTENTS_H_
 #define HEADLESS_PUBLIC_HEADLESS_WEB_CONTENTS_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "headless/public/headless_export.h"
 #include "url/gurl.h"
 
 namespace headless {
 
 // Class representing contents of a browser tab. Should be accessed from browser
 // main thread.
 class HEADLESS_EXPORT HeadlessWebContents {
  public:
   virtual ~HeadlessWebContents() {}
 
   // TODO(skyostil): Replace this with an equivalent client API.
   class Observer {
    public:
-    // Will be called on browser thread.
-    virtual void DocumentOnLoadCompletedInMainFrame() = 0;
-    virtual void DidFinishNavigation(bool success) = 0;
+    // All the following notifications will be called on browser main thread.
+    virtual void DocumentOnLoadCompletedInMainFrame(){};
+    virtual void DidFinishNavigation(bool success){};
+
+    // After this event, this HeadlessWebContents instance is ready to be
+    // controlled using a DevTools client.
+    virtual void WebContentsReady(){};
 
    protected:
     Observer() {}
     virtual ~Observer() {}
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Observer);
   };
 
-  // TODO(skyostil): Replace this with an equivalent client API.
-  virtual bool OpenURL(const GURL& url) = 0;
-
   // Add or remove an observer to receive events from this WebContents.
   // |observer| must outlive this class or be removed prior to being destroyed.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
 
  private:
   friend class HeadlessWebContentsImpl;
   HeadlessWebContents() {}
 
   DISALLOW_COPY_AND_ASSIGN(HeadlessWebContents);
 };
 
 }  // namespace headless
 
 #endif  // HEADLESS_PUBLIC_HEADLESS_WEB_CONTENTS_H_