Remove all blimp client code.

blimp/client/public/contents/blimp_contents_observer.h

-// Copyright 2016 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 BLIMP_CLIENT_PUBLIC_CONTENTS_BLIMP_CONTENTS_OBSERVER_H_
-#define BLIMP_CLIENT_PUBLIC_CONTENTS_BLIMP_CONTENTS_OBSERVER_H_
-
-#include "base/macros.h"
-#include "url/gurl.h"
-
-namespace blimp {
-namespace client {
-
-class BlimpContents;
-
-// An observer API implemented by classes which are interested in various events
-// related to BlimpContents.
-class BlimpContentsObserver {
- public:
-  virtual ~BlimpContentsObserver();
-
-  // Invoked when the navigation state of the BlimpContents has changed.
-  virtual void OnNavigationStateChanged() {}
-
-  // Invoked when the BlimpContents starts or stops loading resources.
-  virtual void OnLoadingStateChanged(bool loading) {}
-
-  // Invoked when the BlimpContents starts or stops loading a page.
-  virtual void OnPageLoadingStateChanged(bool loading) {}
-
-  // Called by BlimpContentsDying().
-  virtual void OnContentsDestroyed() {}
-
-  // Invoke when the destructor of blimp contents is called. This will clear
-  // the contents_ to nullptr.
-  void BlimpContentsDying();
-
-  BlimpContents* blimp_contents() { return contents_; }
-
- protected:
-  explicit BlimpContentsObserver(BlimpContents* blimp_contents);
-
- private:
-  // The BlimpContents being tracked by this BlimpContentsObserver.
-  BlimpContents* contents_;
-
-  DISALLOW_COPY_AND_ASSIGN(BlimpContentsObserver);
-};
-
-}  // namespace client
-}  // namespace blimp
-
-#endif  // BLIMP_CLIENT_PUBLIC_CONTENTS_BLIMP_CONTENTS_OBSERVER_H_