1 files changed, 91 insertions, 0 deletions
diff --git a/layout/xul/nsIScrollbarMediator.h b/layout/xul/nsIScrollbarMediator.h
new file mode 100644
index 000000000..87b82e3d9
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+++ b/layout/xul/nsIScrollbarMediator.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsIScrollbarMediator_h___
+#define nsIScrollbarMediator_h___
+
+#include "nsQueryFrame.h"
+#include "nsCoord.h"
+
+class nsScrollbarFrame;
+class nsIFrame;
+
+class nsIScrollbarMediator : public nsQueryFrame
+{
+public:
+  NS_DECL_QUERYFRAME_TARGET(nsIScrollbarMediator)
+
+  /**
+   * The aScrollbar argument denotes the scrollbar that's firing the notification.
+   * aScrollbar is never null.
+   * aDirection is either -1, 0, or 1.
+   */
+
+  /**
+   * When set to ENABLE_SNAP, additional scrolling will be performed after the
+   * scroll operation to maintain the constraints set by CSS Scroll snapping.
+   * The additional scrolling may include asynchronous smooth scrolls that
+   * continue to animate after the initial scroll position has been set.
+   */
+  enum ScrollSnapMode { DISABLE_SNAP, ENABLE_SNAP };
+
+  /**
+   * One of the following three methods is called when the scrollbar's button is
+   * clicked.
+   * @note These methods might destroy the frame, pres shell, and other objects.
+   */
+  virtual void ScrollByPage(nsScrollbarFrame* aScrollbar, int32_t aDirection,
+                            ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
+  virtual void ScrollByWhole(nsScrollbarFrame* aScrollbar, int32_t aDirection,
+                            ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
+  virtual void ScrollByLine(nsScrollbarFrame* aScrollbar, int32_t aDirection,
+                            ScrollSnapMode aSnap = DISABLE_SNAP) = 0;
+  /**
+   * RepeatButtonScroll is called when the scrollbar's button is held down. When the
+   * button is first clicked the increment is set; RepeatButtonScroll adds this
+   * increment to the current position.
+   * @note This method might destroy the frame, pres shell, and other objects.
+   */
+  virtual void RepeatButtonScroll(nsScrollbarFrame* aScrollbar) = 0;
+  /**
+   * aOldPos and aNewPos are scroll positions.
+   * The scroll positions start with zero at the left edge; implementors that want
+   * zero at the right edge for RTL content will need to adjust accordingly.
+   * (See ScrollFrameHelper::ThumbMoved in nsGfxScrollFrame.cpp.)
+   * @note This method might destroy the frame, pres shell, and other objects.
+   */
+  virtual void ThumbMoved(nsScrollbarFrame* aScrollbar,
+                          nscoord aOldPos,
+                          nscoord aNewPos) = 0;
+  /**
+   * Called when the scroll bar thumb, slider, or any other component is
+   * released.
+   */
+  virtual void ScrollbarReleased(nsScrollbarFrame* aScrollbar) = 0;
+  virtual void VisibilityChanged(bool aVisible) = 0;
+
+  /**
+   * Obtain the frame for the horizontal or vertical scrollbar, or null
+   * if there is no such box.
+   */
+  virtual nsIFrame* GetScrollbarBox(bool aVertical) = 0;
+  /**
+   * Show or hide scrollbars on 2 fingers touch.
+   * Subclasses should call their ScrollbarActivity's corresponding methods.
+   */
+  virtual void ScrollbarActivityStarted() const = 0;
+  virtual void ScrollbarActivityStopped() const = 0;
+
+  virtual bool IsScrollbarOnRight() const = 0;
+
+  /**
+   * Returns true if the mediator is asking the scrollbar to suppress
+   * repainting itself on changes.
+   */
+  virtual bool ShouldSuppressScrollbarRepaints() const = 0;
+};
+
+#endif
+