gecko-dev/layout/base/nsIPresShell.h

704 lines
25 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Steve Clark <buster@netscape.com>
* Dan Rosen <dr@netscape.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK *****
*
* This Original Code has been modified by IBM Corporation.
* Modifications made by IBM described herein are
* Copyright (c) International Business Machines
* Corporation, 2000
*
* Modifications to Mozilla code or documentation
* identified per MPL Section 3.3
*
* Date Modified by Description of modification
* 05/03/2000 IBM Corp. Observer related defines for reflow
*/
#ifndef nsIPresShell_h___
#define nsIPresShell_h___
#include "nsISupports.h"
#include "nsCoord.h"
#include "nsEvent.h"
#include "nsReflowType.h"
#include "nsCompatibility.h"
#include "nsCOMArray.h"
#include "nsFrameManagerBase.h"
#include "mozFlushType.h"
#include <stdio.h> // for FILE definition
class nsIAtom;
class nsIContent;
class nsIContentIterator;
class nsIDocument;
class nsIDocumentObserver;
class nsIFrame;
class nsPresContext;
class nsStyleSet;
class nsIViewManager;
class nsIDeviceContext;
class nsIRenderingContext;
class nsIPageSequenceFrame;
class nsString;
class nsAString;
class nsStringArray;
class nsICaret;
class nsStyleContext;
class nsIFrameSelection;
class nsFrameManager;
class nsILayoutHistoryState;
class nsIReflowCallback;
class nsISupportsArray;
class nsIDOMNode;
class nsHTMLReflowCommand;
class nsIStyleFrameConstruction;
class nsIStyleSheet;
class nsCSSFrameConstructor;
#define NS_IPRESSHELL_IID \
{ 0x3b864134, 0x4e25, 0x4cd0, \
{0xa6, 0x9e, 0x34, 0x14, 0x13, 0x18, 0x39, 0x58} }
// Constants uses for ScrollFrameIntoView() function
#define NS_PRESSHELL_SCROLL_TOP 0
#define NS_PRESSHELL_SCROLL_BOTTOM 100
#define NS_PRESSHELL_SCROLL_LEFT 0
#define NS_PRESSHELL_SCROLL_RIGHT 100
#define NS_PRESSHELL_SCROLL_CENTER 50
#define NS_PRESSHELL_SCROLL_ANYWHERE -1
#define NS_PRESSHELL_SCROLL_IF_NOT_VISIBLE -2
// debug VerifyReflow flags
#define VERIFY_REFLOW_ON 0x01
#define VERIFY_REFLOW_NOISY 0x02
#define VERIFY_REFLOW_ALL 0x04
#define VERIFY_REFLOW_DUMP_COMMANDS 0x08
#define VERIFY_REFLOW_NOISY_RC 0x10
#define VERIFY_REFLOW_REALLY_NOISY_RC 0x20
#define VERIFY_REFLOW_INCLUDE_SPACE_MANAGER 0x40
#define VERIFY_REFLOW_DURING_RESIZE_REFLOW 0x80
#ifdef IBMBIDI // Constant for Set/Get CaretBidiLevel
#define BIDI_LEVEL_UNDEFINED 0x80
#endif
// for PostAttributeChanged
enum nsAttributeChangeType {
eChangeType_Set = 0, // Set attribute
eChangeType_Remove = 1 // Remove attribute
};
/**
* Presentation shell interface. Presentation shells are the
* controlling point for managing the presentation of a document. The
* presentation shell holds a live reference to the document, the
* presentation context, the style manager, the style set and the root
* frame. <p>
*
* When this object is Release'd, it will release the document, the
* presentation context, the style manager, the style set and the root
* frame.
*/
// hack to make egcs / gcc 2.95.2 happy
class nsIPresShell_base : public nsISupports
{
public:
NS_DEFINE_STATIC_IID_ACCESSOR(NS_IPRESSHELL_IID)
};
class nsIPresShell : public nsIPresShell_base
{
public:
NS_IMETHOD Init(nsIDocument* aDocument,
nsPresContext* aPresContext,
nsIViewManager* aViewManager,
nsStyleSet* aStyleSet,
nsCompatibility aCompatMode) = 0;
/**
* All callers are responsible for calling |Destroy| after calling
* |EndObservingDocument|. It needs to be separate only because form
* controls incorrectly store their data in the frames rather than the
* content model and printing calls |EndObservingDocument| multiple
* times to make form controls behave nicely when printed.
*/
NS_IMETHOD Destroy() = 0;
// All frames owned by the shell are allocated from an arena. They are also recycled
// using free lists (separate free lists being maintained for each size_t).
// Methods for recycling frames.
virtual void* AllocateFrame(size_t aSize) = 0;
virtual void FreeFrame(size_t aSize, void* aFreeChunk) = 0;
// Dynamic stack memory allocation
NS_IMETHOD PushStackMemory() = 0;
NS_IMETHOD PopStackMemory() = 0;
NS_IMETHOD AllocateStackMemory(size_t aSize, void** aResult) = 0;
nsIDocument* GetDocument() { return mDocument; }
nsPresContext* GetPresContext() { return mPresContext; }
nsIViewManager* GetViewManager() { return mViewManager; }
#ifdef _IMPL_NS_LAYOUT
nsStyleSet* StyleSet() { return mStyleSet; }
nsCSSFrameConstructor* FrameConstructor()
{
return mFrameConstructor;
}
nsFrameManager* FrameManager() const {
return NS_REINTERPRET_CAST(nsFrameManager*,
&NS_CONST_CAST(nsIPresShell*, this)->mFrameManager);
}
#endif
// These two methods are used only by viewer
NS_IMETHOD GetActiveAlternateStyleSheet(nsString& aSheetTitle) = 0;
NS_IMETHOD SelectAlternateStyleSheet(const nsString& aSheetTitle) = 0;
/* Enable/disable author style level. Disabling author style disables the entire
* author level of the cascade, including the HTML preshint level.
*/
// XXX these could easily be inlined, but there is a circular #include
// problem with nsStyleSet.
NS_HIDDEN_(void) SetAuthorStyleDisabled(PRBool aDisabled);
NS_HIDDEN_(PRBool) GetAuthorStyleDisabled();
/*
* Called when stylesheets are added/removed/enabled/disabled to rebuild
* all style data for a given pres shell without necessarily reconstructing
* all of the frames.
*/
virtual NS_HIDDEN_(void) ReconstructStyleDataExternal();
NS_HIDDEN_(void) ReconstructStyleDataInternal();
#ifdef _IMPL_NS_LAYOUT
void ReconstructStyleData() { ReconstructStyleDataInternal(); }
#else
void ReconstructStyleData() { ReconstructStyleDataExternal(); }
#endif
/** Setup all style rules required to implement preferences
* - used for background/text/link colors and link underlining
* may be extended for any prefs that are implemented via style rules
* - aForceReflow argument is used to force a full reframe to make the rules show
* (only used when the current page needs to reflect changed pref rules)
*
* - initially created for bugs 31816, 20760, 22963
*/
NS_IMETHOD SetPreferenceStyleRules(PRBool aForceReflow) = 0;
/**
* Gather titles of all selectable (alternate and preferred) style sheets
* fills void array with nsString* caller must free strings
*/
NS_IMETHOD ListAlternateStyleSheets(nsStringArray& aTitleList) = 0;
/**
* FrameSelection will return the Frame based selection API.
* You cannot go back and forth anymore with QI between nsIDOM sel and
* nsIFrame sel.
*/
nsIFrameSelection* FrameSelection() { return mSelection; }
// Make shell be a document observer
NS_IMETHOD BeginObservingDocument() = 0;
// Make shell stop being a document observer
NS_IMETHOD EndObservingDocument() = 0;
/**
* Determine if InitialReflow() was previously called.
* @param aDidInitialReflow PR_TRUE if InitalReflow() was previously called,
* PR_FALSE otherwise.
*/
NS_IMETHOD GetDidInitialReflow(PRBool *aDidInitialReflow) = 0;
/**
* Perform the initial reflow. Constructs the frame for the root content
* object and then reflows the frame model into the specified width and
* height.
*
* The coordinates for aWidth and aHeight must be in standard nscoord's.
*/
NS_IMETHOD InitialReflow(nscoord aWidth, nscoord aHeight) = 0;
/**
* Reflow the frame model into a new width and height. The
* coordinates for aWidth and aHeight must be in standard nscoord's.
*/
NS_IMETHOD ResizeReflow(nscoord aWidth, nscoord aHeight) = 0;
/**
* Reflow the frame model with a reflow reason of eReflowReason_StyleChange
*/
NS_IMETHOD StyleChangeReflow() = 0;
/**
* This calls through to the frame manager to get the root frame.
* Callers inside of gklayout should use FrameManager()->GetRootFrame()
* instead, as it's more efficient.
*/
virtual NS_HIDDEN_(nsIFrame*) GetRootFrame() const;
/**
* Returns the page sequence frame associated with the frame hierarchy.
* Returns NULL if not a paginated view.
*/
NS_IMETHOD GetPageSequenceFrame(nsIPageSequenceFrame** aResult) const = 0;
/**
* Gets the primary frame associated with the content object. This is a
* helper function that just forwards the request to the frame manager.
*
* The primary frame is the frame that is most closely associated with the
* content. A frame is more closely associated with the content that another
* frame if the one frame contains directly or indirectly the other frame (e.g.,
* when a frame is scrolled there is a scroll frame that contains the frame
* being scrolled). The primary frame is always the first-in-flow.
*
* In the case of absolutely positioned elements and floated elements,
* the primary frame is the frame that is out of the flow and not the
* placeholder frame.
*/
NS_IMETHOD GetPrimaryFrameFor(nsIContent* aContent,
nsIFrame** aPrimaryFrame) const = 0;
/**
* Returns a layout object associated with the primary frame for the content object.
*
* @param aContent the content object for which we seek a layout object
* @param aResult the resulting layout object as an nsISupports, if found. Refcounted.
*/
NS_IMETHOD GetLayoutObjectFor(nsIContent* aContent,
nsISupports** aResult) const = 0;
/**
* Gets the placeholder frame associated with the specified frame. This is
* a helper frame that forwards the request to the frame manager.
*/
NS_IMETHOD GetPlaceholderFrameFor(nsIFrame* aFrame,
nsIFrame** aPlaceholderFrame) const = 0;
/**
* Reflow commands
*/
NS_IMETHOD AppendReflowCommand(nsHTMLReflowCommand* aReflowCommand) = 0;
NS_IMETHOD CancelReflowCommand(nsIFrame* aTargetFrame, nsReflowType* aCmdType) = 0;
NS_IMETHOD CancelAllReflowCommands() = 0;
/**
* Recreates the frames for a node
*/
NS_IMETHOD RecreateFramesFor(nsIContent* aContent) = 0;
/**
* Determine if it is safe to flush all pending notifications
* @param aIsSafeToFlush PR_TRUE if it is safe, PR_FALSE otherwise.
*
*/
NS_IMETHOD IsSafeToFlush(PRBool& aIsSafeToFlush) = 0;
/**
* Flush pending notifications of the type specified. This method
* will not affect the content model; it'll just affect style and
* frames. Callers that actually want up-to-date presentation (other
* than the document itself) should probably be calling
* nsIDocument::FlushPendingNotifications.
*
* @param aType the type of notifications to flush
*/
NS_IMETHOD FlushPendingNotifications(mozFlushType aType) = 0;
/**
* Post a request to handle a DOM event after Reflow has finished.
*/
NS_IMETHOD PostDOMEvent(nsIContent* aContent, nsEvent* aEvent)=0;
/**
* Post a request to set and attribute after reflow has finished.
*/
NS_IMETHOD PostAttributeChange(nsIContent* aContent,
PRInt32 aNameSpaceID,
nsIAtom* aName,
const nsString& aValue,
PRBool aNotify,
nsAttributeChangeType aType) = 0;
NS_IMETHOD PostReflowCallback(nsIReflowCallback* aCallback) = 0;
NS_IMETHOD CancelReflowCallback(nsIReflowCallback* aCallback) = 0;
/**
* Reflow batching
*/
NS_IMETHOD BeginReflowBatching() = 0;
NS_IMETHOD EndReflowBatching(PRBool aFlushPendingReflows) = 0;
NS_IMETHOD GetReflowBatchingStatus(PRBool* aIsBatching) = 0;
NS_IMETHOD ClearFrameRefs(nsIFrame* aFrame) = 0;
/**
* Given a frame, create a rendering context suitable for use with
* the frame.
*/
NS_IMETHOD CreateRenderingContext(nsIFrame *aFrame,
nsIRenderingContext** aContext) = 0;
/**
* Notification that we were unable to render a replaced element.
* Called when the replaced element can not be rendered, and we should
* instead render the element's contents.
* The content object associated with aFrame should either be a IMG
* element, an OBJECT element, or an APPLET element
*/
NS_IMETHOD CantRenderReplacedElement(nsIFrame* aFrame) = 0;
/**
* Informs the pres shell that the document is now at the anchor with
* the given name. If |aScroll| is true, scrolls the view of the
* document so that the anchor with the specified name is displayed at
* the top of the window. If |aAnchorName| is empty, then this informs
* the pres shell that there is no current target, and |aScroll| must
* be false.
*/
NS_IMETHOD GoToAnchor(const nsAString& aAnchorName, PRBool aScroll) = 0;
/**
* Scrolls the view of the document so that the frame is displayed at the
* top of the window.
*
* @param aFrame The frame to scroll into view
* @param aVPercent How to align the frame vertically. A value of 0
* (NS_PRESSHELL_SCROLL_TOP) means the frame's upper edge is
* aligned with the top edge of the visible area. A value of
* 100 (NS_PRESSHELL_SCROLL_BOTTOM) means the frame's bottom
* edge is aligned with the bottom edge of the visible area.
* For values in between, the point "aVPercent" down the frame
* is placed at the point "aVPercent" down the visible area. A
* value of 50 (NS_PRESSHELL_SCROLL_CENTER) centers the frame
* vertically. A value of NS_PRESSHELL_SCROLL_ANYWHERE means move
* the frame the minimum amount necessary in order for the entire
* frame to be visible vertically (if possible)
* @param aHPercent How to align the frame horizontally. A value of 0
* (NS_PRESSHELL_SCROLL_LEFT) means the frame's left edge is
* aligned with the left edge of the visible area. A value of
* 100 (NS_PRESSHELL_SCROLL_RIGHT) means the frame's right
* edge is aligned with the right edge of the visible area.
* For values in between, the point "aVPercent" across the frame
* is placed at the point "aVPercent" across the visible area.
* A value of 50 (NS_PRESSHELL_SCROLL_CENTER) centers the frame
* horizontally . A value of NS_PRESSHELL_SCROLL_ANYWHERE means move
* the frame the minimum amount necessary in order for the entire
* frame to be visible horizontally (if possible)
*/
NS_IMETHOD ScrollFrameIntoView(nsIFrame *aFrame,
PRIntn aVPercent,
PRIntn aHPercent) const = 0;
/**
* Suppress notification of the frame manager that frames are
* being destroyed.
*/
NS_IMETHOD SetIgnoreFrameDestruction(PRBool aIgnore) = 0;
/**
* Notification sent by a frame informing the pres shell that it is about to
* be destroyed.
* This allows any outstanding references to the frame to be cleaned up
*/
NS_IMETHOD NotifyDestroyingFrame(nsIFrame* aFrame) = 0;
/**
* Notify the Clipboard that we have something to copy.
*/
NS_IMETHOD DoCopy() = 0;
/**
* Get link location.
*/
NS_IMETHOD GetLinkLocation(nsIDOMNode* aNode, nsAString& aLocation) = 0;
/**
* Get the doc or the selection as text or html.
*/
NS_IMETHOD DoGetContents(const nsACString& aMimeType, PRUint32 aFlags, PRBool aSelectionOnly, nsAString& outValue) = 0;
/**
* Get the caret, if it exists. AddRefs it.
*/
NS_IMETHOD GetCaret(nsICaret **aOutCaret) = 0;
/**
* Should the images have borders etc. Actual visual effects are determined
* by the frames. Visual effects may not effect layout, only display.
* Takes effect on next repaint, does not force a repaint itself.
*
* @param aEnabled if PR_TRUE, visual selection effects are enabled
* if PR_FALSE visual selection effects are disabled
* @return always NS_OK
*/
NS_IMETHOD SetSelectionFlags(PRInt16 aInEnable) = 0;
/**
* Gets the current state of non text selection effects
* @param aEnabled [OUT] set to the current state of non text selection,
* as set by SetDisplayNonTextSelection
* @return if aOutEnabled==null, returns NS_ERROR_INVALID_ARG
* else NS_OK
*/
NS_IMETHOD GetSelectionFlags(PRInt16 *aOutEnabled) = 0;
/**
* Interface to dispatch events via the presshell
*/
NS_IMETHOD HandleEventWithTarget(nsEvent* aEvent,
nsIFrame* aFrame,
nsIContent* aContent,
PRUint32 aFlags,
nsEventStatus* aStatus) = 0;
/**
* Dispatch event to content only (NOT full processing)
*/
NS_IMETHOD HandleDOMEventWithTarget(nsIContent* aTargetContent,
nsEvent* aEvent,
nsEventStatus* aStatus) = 0;
/**
* Gets the current target event frame from the PresShell
*/
NS_IMETHOD GetEventTargetFrame(nsIFrame** aFrame) = 0;
/**
* Gets the current target event frame from the PresShell
*/
NS_IMETHOD GetEventTargetContent(nsEvent* aEvent, nsIContent** aContent) = 0;
/**
* Get and set the history state for the current document
*/
NS_IMETHOD CaptureHistoryState(nsILayoutHistoryState** aLayoutHistoryState, PRBool aLeavingPage = PR_FALSE) = 0;
/**
* Determine if reflow is currently locked
* @param aIsReflowLocked returns PR_TRUE if reflow is locked, PR_FALSE otherwise
*/
NS_IMETHOD IsReflowLocked(PRBool* aIsLocked) = 0;
/**
* Returns a content iterator to iterate the generated content nodes.
* You must specify whether you want to iterate the "before" generated
* content or the "after" generated content. If there is no generated
* content of the specified type for the promary frame associated with
* with the content object then NULL is returned
*/
enum GeneratedContentType {Before, After};
NS_IMETHOD GetGeneratedContentIterator(nsIContent* aContent,
GeneratedContentType aType,
nsIContentIterator** aIterator) const = 0;
/**
* Store the nsIAnonymousContentCreator-generated anonymous
* content that's associated with an element. The new anonymous content
* is added to whatever anonymous content might already be associated with
* the element.
* @param aContent the element with which the anonymous
* content is to be associated with
* @param aAnonymousElements an array of nsIContent
* objects, or null to indicate that any anonymous
* content should be dissociated from the aContent
*/
NS_IMETHOD SetAnonymousContentFor(nsIContent* aContent, nsISupportsArray* aAnonymousElements) = 0;
/**
* Retrieve the nsIAnonymousContentCreator-generated anonymous
* content that's associated with an element.
* @param aContent the element for which to retrieve the
* associated anonymous content
* @param aAnonymousElements an array of nsIContent objects,
* or null to indicate that there are no anonymous elements
* associated with aContent
*/
NS_IMETHOD GetAnonymousContentFor(nsIContent* aContent, nsISupportsArray** aAnonymousElements) = 0;
/**
* Release all nsIAnonymousContentCreator-generated
* anonymous content associated with the shell.
*/
NS_IMETHOD ReleaseAnonymousContent() = 0;
/**
* Called to find out if painting is suppressed for this presshell. If it is suppressd,
* we don't allow the painting of any layer but the background, and we don't
* recur into our children.
*/
NS_IMETHOD IsPaintingSuppressed(PRBool* aResult)=0;
/**
* Unsuppress painting.
*/
NS_IMETHOD UnsuppressPainting() = 0;
/**
* Called to disable nsITheme support in a specific presshell.
*/
NS_IMETHOD DisableThemeSupport() = 0;
/**
* Indicates whether theme support is enabled.
*/
virtual PRBool IsThemeSupportEnabled() = 0;
/**
* Get the set of agent style sheets for this presentation
*/
virtual nsresult GetAgentStyleSheets(nsCOMArray<nsIStyleSheet>& aSheets) = 0;
/**
* Replace the set of agent style sheets
*/
virtual nsresult SetAgentStyleSheets(const nsCOMArray<nsIStyleSheet>& aSheets) = 0;
/**
* Add an override style sheet for this presentation
*/
virtual nsresult AddOverrideStyleSheet(nsIStyleSheet *aSheet) = 0;
/**
* Remove an override style sheet
*/
virtual nsresult RemoveOverrideStyleSheet(nsIStyleSheet *aSheet) = 0;
/**
* Reconstruct frames for all elements in the document
*/
virtual nsresult ReconstructFrames() = 0;
/**
* See if reflow verification is enabled. To enable reflow verification add
* "verifyreflow:1" to your NSPR_LOG_MODULES environment variable
* (any non-zero debug level will work). Or, call SetVerifyReflowEnable
* with PR_TRUE.
*/
static PRBool GetVerifyReflowEnable();
/**
* Set the verify-reflow enable flag.
*/
static void SetVerifyReflowEnable(PRBool aEnabled);
/**
* Get the flags associated with the VerifyReflow debug tool
*/
static PRInt32 GetVerifyReflowFlags();
#ifdef MOZ_REFLOW_PERF
NS_IMETHOD DumpReflows() = 0;
NS_IMETHOD CountReflows(const char * aName, PRUint32 aType, nsIFrame * aFrame) = 0;
NS_IMETHOD PaintCount(const char * aName,
nsIRenderingContext* aRenderingContext,
nsPresContext * aPresContext,
nsIFrame * aFrame,
PRUint32 aColor) = 0;
NS_IMETHOD SetPaintFrameCount(PRBool aOn) = 0;
#endif
#ifdef IBMBIDI
/**
* SetCaretBidiLevel will set the Bidi embedding level for the cursor. 0-63
*/
NS_IMETHOD SetCaretBidiLevel(PRUint8 aLevel) = 0;
/**
* GetCaretBidiLevel will get the Bidi embedding level for the cursor. 0-63
*/
NS_IMETHOD GetCaretBidiLevel(PRUint8 *aOutLevel) = 0;
/**
* UndefineCaretBidiLevel will set the Bidi embedding level for the cursor to an out-of-range value
*/
NS_IMETHOD UndefineCaretBidiLevel(void) = 0;
/**
* Reconstruct and reflow frame model
*/
NS_IMETHOD BidiStyleChangeReflow(void) = 0;
#endif
#ifdef DEBUG
// Debugging hooks
virtual void ListStyleContexts(nsIFrame *aRootFrame, FILE *out,
PRInt32 aIndent = 0) = 0;
virtual void ListStyleSheets(FILE *out, PRInt32 aIndent = 0) = 0;
#endif
protected:
// IMPORTANT: The ownership implicit in the following member variables
// has been explicitly checked. If you add any members to this class,
// please make the ownership explicit (pinkerton, scc).
// these are the same Document and PresContext owned by the DocViewer.
// we must share ownership.
nsIDocument* mDocument; // [STRONG]
nsPresContext* mPresContext; // [STRONG]
nsStyleSet* mStyleSet; // [OWNS]
nsCSSFrameConstructor* mFrameConstructor; // [OWNS]
nsIViewManager* mViewManager; // [WEAK] docViewer owns it so I don't have to
nsIFrameSelection* mSelection;
nsFrameManagerBase mFrameManager; // [OWNS]
PRPackedBool mStylesHaveChanged;
};
/**
* Create a new empty presentation shell. Upon success, call Init
* before attempting to use the shell.
*/
nsresult
NS_NewPresShell(nsIPresShell** aInstancePtrResult);
#endif /* nsIPresShell_h___ */