1 files changed, 100 insertions, 0 deletions
diff --git a/layout/base/nsFrameManager.h b/layout/base/nsFrameManager.h
new file mode 100644
index 0000000000..fa68cb79f5
--- /dev/null
+++ b/layout/base/nsFrameManager.h
@@ -0,0 +1,100 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/* Owns the frame tree and provides APIs to manipulate it */
+
+#ifndef _nsFrameManager_h_
+#define _nsFrameManager_h_
+
+#include "nsDebug.h"
+#include "mozilla/Attributes.h"
+#include "nsFrameList.h"
+
+class nsContainerFrame;
+class nsIFrame;
+class nsILayoutHistoryState;
+class nsPlaceholderFrame;
+class nsWindowSizes;
+
+namespace mozilla {
+struct FrameDestroyContext;
+class PresShell;
+}  // namespace mozilla
+
+/**
+ * Frame manager interface. The frame manager owns the frame tree model, and
+ * handles structural manipulations to it, such as appending and inserting a
+ * list of frames to a parent frame, or removing a child frame from a parent
+ * frame.
+ */
+class nsFrameManager {
+ public:
+  using DestroyContext = mozilla::FrameDestroyContext;
+
+  explicit nsFrameManager(mozilla::PresShell* aPresShell)
+      : mPresShell(aPresShell), mRootFrame(nullptr) {
+    MOZ_ASSERT(mPresShell, "need a pres shell");
+  }
+  ~nsFrameManager();
+
+  /*
+   * Gets and sets the root frame (typically the viewport). The lifetime of the
+   * root frame is controlled by the frame manager. When the frame manager is
+   * destroyed, it destroys the entire frame hierarchy.
+   */
+  nsIFrame* GetRootFrame() const { return mRootFrame; }
+  void SetRootFrame(nsIFrame* aRootFrame) {
+    NS_ASSERTION(!mRootFrame, "already have a root frame");
+    mRootFrame = aRootFrame;
+  }
+
+  /*
+   * After Destroy is called, it is an error to call any FrameManager methods.
+   * Destroy should be called when the frame tree managed by the frame
+   * manager is no longer being displayed.
+   */
+  void Destroy();
+
+  // Functions for manipulating the frame model
+  void AppendFrames(nsContainerFrame* aParentFrame,
+                    mozilla::FrameChildListID aListID,
+                    nsFrameList&& aFrameList);
+
+  void InsertFrames(nsContainerFrame* aParentFrame,
+                    mozilla::FrameChildListID aListID, nsIFrame* aPrevFrame,
+                    nsFrameList&& aFrameList);
+
+  void RemoveFrame(DestroyContext&, mozilla::FrameChildListID, nsIFrame*);
+
+  /*
+   * Capture/restore frame state for the frame subtree rooted at aFrame.
+   * aState is the document state storage object onto which each frame
+   * stores its state.  Callers of CaptureFrameState are responsible for
+   * traversing next continuations of special siblings of aFrame as
+   * needed; this method will only work with actual frametree descendants
+   * of aFrame.
+   */
+
+  void CaptureFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
+
+  void RestoreFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
+
+  /*
+   * Add/restore state for one frame
+   */
+  void CaptureFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
+
+  void RestoreFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
+
+  void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
+
+ protected:
+  // weak link, because the pres shell owns us
+  mozilla::PresShell* MOZ_NON_OWNING_REF mPresShell;
+  nsIFrame* mRootFrame;
+};
+
+#endif