text: /*
   * Copyright (C) 2013 Google Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *     * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following disclaimer
   * in the documentation and/or other materials provided with the
   * distribution.
   *     * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_FULLSCREEN_CONTROLLER_H_
  #define THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_FULLSCREEN_CONTROLLER_H_
  
  #include <memory>
  
  #include "third_party/blink/renderer/core/core_export.h"
  #include "third_party/blink/renderer/platform/geometry/float_point.h"
  #include "third_party/blink/renderer/platform/geometry/int_size.h"
  #include "third_party/blink/renderer/platform/graphics/color.h"
  
  namespace blink {
  
  class Element;
  class FullscreenOptions;
  class LocalFrame;
  class WebViewImpl;
  
  // FullscreenController is a per-WebView class that manages the transition into
  // and out of fullscreen, including restoring scroll offset and scale after
  // exiting fullscreen. It is (indirectly) used by the Fullscreen class.
  class CORE_EXPORT FullscreenController {
   public:
    static std::unique_ptr<FullscreenController> Create(WebViewImpl*);
  
    // Called by Fullscreen (via ChromeClient) to request entering or exiting
    // fullscreen.
    void EnterFullscreen(LocalFrame&, const FullscreenOptions&);
    void ExitFullscreen(LocalFrame&);
  
    // Called by content::RenderWidget (via WebWidget) to notify that we've
    // entered or exited fullscreen. This can be because we requested it, or it
    // can be initiated by the browser directly.
    void DidEnterFullscreen();
    void DidExitFullscreen();
  
    // Called by Fullscreen (via ChromeClient) to notify that the fullscreen
    // element has changed.
    void FullscreenElementChanged(Element* old_element, Element* new_element);
  
    bool IsFullscreenOrTransitioning() const { return state_ != State::kInitial; }
  
    void UpdateSize();
  
    void DidUpdateLayout();
  
   protected:
    explicit FullscreenController(WebViewImpl*);
  
   private:
    void UpdatePageScaleConstraints(bool remove_constraints);
    void RestoreBackgroundColorOverride();
  
    WebViewImpl* web_view_base_;
  
    // State is used to avoid unnecessary enter/exit requests, and to restore the
    // initial*_ after the first layout upon exiting fullscreen. Typically, the
    // state goes through every state from Initial to NeedsScrollAndScaleRestore
    // and then back to Initial, but the are two exceptions:
    //  1. DidExitFullscreen() can transition from any non-Initial state to
    //     NeedsScrollAndScaleRestore, in case of a browser-intiated exit.
    //  2. EnterFullscreen() can transition from NeedsScrollAndScaleRestore to
    //     EnteringFullscreen, in case of a quick exit+enter.
    enum class State {
      kInitial,
      kEnteringFullscreen,
      kFullscreen,
      kExitingFullscreen,
      kNeedsScrollAndScaleRestore
    };
    State state_ = State::kInitial;
  
    float initial_page_scale_factor_ = 0.0f;
    IntSize initial_scroll_offset_;
    FloatPoint initial_visual_viewport_offset_;
    bool initial_background_color_override_enabled_ = false;
    RGBA32 initial_background_color_override_ = Color::kTransparent;
  };
  
  }  // namespace blink
  
  #endif
  