gecko/layout/base/nsFrameManager.cpp
Birunthan Mohanathas b823b8896b Bug 784739 - Switch from NULL to nullptr in layout/; r=ehsan
--HG--
extra : rebase_source : 0d0d9e11be9d39e4457bddd0bac7e19a50b91b0b
2013-10-08 14:47:21 -04:00

739 lines
23 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim:cindent:ts=2:et:sw=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/.
*
* 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
* 04/20/2000 IBM Corp. OS/2 VisualAge build.
*/
/* storage of the frame tree and information about it */
#include "nscore.h"
#include "nsIPresShell.h"
#include "nsStyleContext.h"
#include "nsCOMPtr.h"
#include "plhash.h"
#include "nsPlaceholderFrame.h"
#include "nsGkAtoms.h"
#include "nsILayoutHistoryState.h"
#include "nsPresState.h"
#include "mozilla/dom/Element.h"
#include "nsIDocument.h"
#include "nsContentUtils.h"
#include "nsError.h"
#include "nsAutoPtr.h"
#include "nsAbsoluteContainingBlock.h"
#include "ChildIterator.h"
#include "nsFrameManager.h"
#include "GeckoProfiler.h"
#include "nsIStatefulFrame.h"
#ifdef DEBUG
//#define DEBUG_UNDISPLAYED_MAP
#else
#undef DEBUG_UNDISPLAYED_MAP
#endif
using namespace mozilla;
using namespace mozilla::dom;
//----------------------------------------------------------------------
struct PlaceholderMapEntry : public PLDHashEntryHdr {
// key (the out of flow frame) can be obtained through placeholder frame
nsPlaceholderFrame *placeholderFrame;
};
static bool
PlaceholderMapMatchEntry(PLDHashTable *table, const PLDHashEntryHdr *hdr,
const void *key)
{
const PlaceholderMapEntry *entry =
static_cast<const PlaceholderMapEntry*>(hdr);
NS_ASSERTION(entry->placeholderFrame->GetOutOfFlowFrame() !=
(void*)0xdddddddd,
"Dead placeholder in placeholder map");
return entry->placeholderFrame->GetOutOfFlowFrame() == key;
}
static PLDHashTableOps PlaceholderMapOps = {
PL_DHashAllocTable,
PL_DHashFreeTable,
PL_DHashVoidPtrKeyStub,
PlaceholderMapMatchEntry,
PL_DHashMoveEntryStub,
PL_DHashClearEntryStub,
PL_DHashFinalizeStub,
nullptr
};
//----------------------------------------------------------------------
// XXXldb This seems too complicated for what I think it's doing, and it
// should also be using pldhash rather than plhash to use less memory.
class nsFrameManagerBase::UndisplayedMap {
public:
UndisplayedMap(uint32_t aNumBuckets = 16) NS_HIDDEN;
~UndisplayedMap(void) NS_HIDDEN;
NS_HIDDEN_(UndisplayedNode*) GetFirstNode(nsIContent* aParentContent);
NS_HIDDEN_(nsresult) AddNodeFor(nsIContent* aParentContent,
nsIContent* aChild, nsStyleContext* aStyle);
NS_HIDDEN_(void) RemoveNodeFor(nsIContent* aParentContent,
UndisplayedNode* aNode);
NS_HIDDEN_(void) RemoveNodesFor(nsIContent* aParentContent);
// Removes all entries from the hash table
NS_HIDDEN_(void) Clear(void);
protected:
/**
* Gets the entry for the provided parent content. If the content
* is a <xbl:children> element, |**aParentContent| is set to
* the parent of the children element.
*/
NS_HIDDEN_(PLHashEntry**) GetEntryFor(nsIContent** aParentContent);
NS_HIDDEN_(void) AppendNodeFor(UndisplayedNode* aNode,
nsIContent* aParentContent);
PLHashTable* mTable;
PLHashEntry** mLastLookup;
};
//----------------------------------------------------------------------
nsFrameManager::~nsFrameManager()
{
NS_ASSERTION(!mPresShell, "nsFrameManager::Destroy never called");
}
void
nsFrameManager::Destroy()
{
NS_ASSERTION(mPresShell, "Frame manager already shut down.");
// Destroy the frame hierarchy.
mPresShell->SetIgnoreFrameDestruction(true);
// Unregister all placeholders before tearing down the frame tree
nsFrameManager::ClearPlaceholderFrameMap();
if (mRootFrame) {
mRootFrame->Destroy();
mRootFrame = nullptr;
}
delete mUndisplayedMap;
mUndisplayedMap = nullptr;
mPresShell = nullptr;
}
//----------------------------------------------------------------------
// Placeholder frame functions
nsPlaceholderFrame*
nsFrameManager::GetPlaceholderFrameFor(const nsIFrame* aFrame)
{
NS_PRECONDITION(aFrame, "null param unexpected");
if (mPlaceholderMap.ops) {
PlaceholderMapEntry *entry = static_cast<PlaceholderMapEntry*>
(PL_DHashTableOperate(const_cast<PLDHashTable*>(&mPlaceholderMap),
aFrame, PL_DHASH_LOOKUP));
if (PL_DHASH_ENTRY_IS_BUSY(entry)) {
return entry->placeholderFrame;
}
}
return nullptr;
}
nsresult
nsFrameManager::RegisterPlaceholderFrame(nsPlaceholderFrame* aPlaceholderFrame)
{
NS_PRECONDITION(aPlaceholderFrame, "null param unexpected");
NS_PRECONDITION(nsGkAtoms::placeholderFrame == aPlaceholderFrame->GetType(),
"unexpected frame type");
if (!mPlaceholderMap.ops) {
if (!PL_DHashTableInit(&mPlaceholderMap, &PlaceholderMapOps, nullptr,
sizeof(PlaceholderMapEntry), 16)) {
mPlaceholderMap.ops = nullptr;
return NS_ERROR_OUT_OF_MEMORY;
}
}
PlaceholderMapEntry *entry = static_cast<PlaceholderMapEntry*>(PL_DHashTableOperate(&mPlaceholderMap,
aPlaceholderFrame->GetOutOfFlowFrame(),
PL_DHASH_ADD));
if (!entry)
return NS_ERROR_OUT_OF_MEMORY;
NS_ASSERTION(!entry->placeholderFrame, "Registering a placeholder for a frame that already has a placeholder!");
entry->placeholderFrame = aPlaceholderFrame;
return NS_OK;
}
void
nsFrameManager::UnregisterPlaceholderFrame(nsPlaceholderFrame* aPlaceholderFrame)
{
NS_PRECONDITION(aPlaceholderFrame, "null param unexpected");
NS_PRECONDITION(nsGkAtoms::placeholderFrame == aPlaceholderFrame->GetType(),
"unexpected frame type");
if (mPlaceholderMap.ops) {
PL_DHashTableOperate(&mPlaceholderMap,
aPlaceholderFrame->GetOutOfFlowFrame(),
PL_DHASH_REMOVE);
}
}
static PLDHashOperator
UnregisterPlaceholders(PLDHashTable* table, PLDHashEntryHdr* hdr,
uint32_t number, void* arg)
{
PlaceholderMapEntry* entry = static_cast<PlaceholderMapEntry*>(hdr);
entry->placeholderFrame->SetOutOfFlowFrame(nullptr);
return PL_DHASH_NEXT;
}
void
nsFrameManager::ClearPlaceholderFrameMap()
{
if (mPlaceholderMap.ops) {
PL_DHashTableEnumerate(&mPlaceholderMap, UnregisterPlaceholders, nullptr);
PL_DHashTableFinish(&mPlaceholderMap);
mPlaceholderMap.ops = nullptr;
}
}
//----------------------------------------------------------------------
nsStyleContext*
nsFrameManager::GetUndisplayedContent(nsIContent* aContent)
{
if (!aContent || !mUndisplayedMap)
return nullptr;
nsIContent* parent = aContent->GetParent();
for (UndisplayedNode* node = mUndisplayedMap->GetFirstNode(parent);
node; node = node->mNext) {
if (node->mContent == aContent)
return node->mStyle;
}
return nullptr;
}
UndisplayedNode*
nsFrameManager::GetAllUndisplayedContentIn(nsIContent* aParentContent)
{
if (!mUndisplayedMap)
return nullptr;
return mUndisplayedMap->GetFirstNode(aParentContent);
}
void
nsFrameManager::SetUndisplayedContent(nsIContent* aContent,
nsStyleContext* aStyleContext)
{
NS_PRECONDITION(!aStyleContext->GetPseudo(),
"Should only have actual elements here");
#ifdef DEBUG_UNDISPLAYED_MAP
static int i = 0;
printf("SetUndisplayedContent(%d): p=%p \n", i++, (void *)aContent);
#endif
NS_ASSERTION(!GetUndisplayedContent(aContent),
"Already have an undisplayed context entry for aContent");
if (! mUndisplayedMap) {
mUndisplayedMap = new UndisplayedMap;
}
nsIContent* parent = aContent->GetParent();
NS_ASSERTION(parent || (mPresShell && mPresShell->GetDocument() &&
mPresShell->GetDocument()->GetRootElement() == aContent),
"undisplayed content must have a parent, unless it's the root "
"element");
mUndisplayedMap->AddNodeFor(parent, aContent, aStyleContext);
}
void
nsFrameManager::ChangeUndisplayedContent(nsIContent* aContent,
nsStyleContext* aStyleContext)
{
NS_ASSERTION(mUndisplayedMap, "no existing undisplayed content");
#ifdef DEBUG_UNDISPLAYED_MAP
static int i = 0;
printf("ChangeUndisplayedContent(%d): p=%p \n", i++, (void *)aContent);
#endif
for (UndisplayedNode* node = mUndisplayedMap->GetFirstNode(aContent->GetParent());
node; node = node->mNext) {
if (node->mContent == aContent) {
node->mStyle = aStyleContext;
return;
}
}
NS_NOTREACHED("no existing undisplayed content");
}
void
nsFrameManager::ClearUndisplayedContentIn(nsIContent* aContent,
nsIContent* aParentContent)
{
#ifdef DEBUG_UNDISPLAYED_MAP
static int i = 0;
printf("ClearUndisplayedContent(%d): content=%p parent=%p --> ", i++, (void *)aContent, (void*)aParentContent);
#endif
if (mUndisplayedMap) {
UndisplayedNode* node = mUndisplayedMap->GetFirstNode(aParentContent);
while (node) {
if (node->mContent == aContent) {
mUndisplayedMap->RemoveNodeFor(aParentContent, node);
#ifdef DEBUG_UNDISPLAYED_MAP
printf( "REMOVED!\n");
#endif
#ifdef DEBUG
// make sure that there are no more entries for the same content
nsStyleContext *context = GetUndisplayedContent(aContent);
NS_ASSERTION(context == nullptr, "Found more undisplayed content data after removal");
#endif
return;
}
node = node->mNext;
}
}
}
void
nsFrameManager::ClearAllUndisplayedContentIn(nsIContent* aParentContent)
{
#ifdef DEBUG_UNDISPLAYED_MAP
static int i = 0;
printf("ClearAllUndisplayedContentIn(%d): parent=%p \n", i++, (void*)aParentContent);
#endif
if (mUndisplayedMap) {
mUndisplayedMap->RemoveNodesFor(aParentContent);
}
// Need to look at aParentContent's content list due to XBL insertions.
// Nodes in aParentContent's content list do not have aParentContent as a
// parent, but are treated as children of aParentContent. We iterate over
// the flattened content list and just ignore any nodes we don't care about.
FlattenedChildIterator iter(aParentContent);
for (nsIContent* child = iter.GetNextChild(); child; child = iter.GetNextChild()) {
if (child->GetParent() != aParentContent) {
ClearUndisplayedContentIn(child, child->GetParent());
}
}
}
//----------------------------------------------------------------------
nsresult
nsFrameManager::AppendFrames(nsIFrame* aParentFrame,
ChildListID aListID,
nsFrameList& aFrameList)
{
if (aParentFrame->IsAbsoluteContainer() &&
aListID == aParentFrame->GetAbsoluteListID()) {
return aParentFrame->GetAbsoluteContainingBlock()->
AppendFrames(aParentFrame, aListID, aFrameList);
} else {
return aParentFrame->AppendFrames(aListID, aFrameList);
}
}
nsresult
nsFrameManager::InsertFrames(nsIFrame* aParentFrame,
ChildListID aListID,
nsIFrame* aPrevFrame,
nsFrameList& aFrameList)
{
NS_PRECONDITION(!aPrevFrame || (!aPrevFrame->GetNextContinuation()
|| (((aPrevFrame->GetNextContinuation()->GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER))
&& !(aPrevFrame->GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER))),
"aPrevFrame must be the last continuation in its chain!");
if (aParentFrame->IsAbsoluteContainer() &&
aListID == aParentFrame->GetAbsoluteListID()) {
return aParentFrame->GetAbsoluteContainingBlock()->
InsertFrames(aParentFrame, aListID, aPrevFrame, aFrameList);
} else {
return aParentFrame->InsertFrames(aListID, aPrevFrame, aFrameList);
}
}
nsresult
nsFrameManager::RemoveFrame(ChildListID aListID,
nsIFrame* aOldFrame)
{
bool wasDestroyingFrames = mIsDestroyingFrames;
mIsDestroyingFrames = true;
// In case the reflow doesn't invalidate anything since it just leaves
// a gap where the old frame was, we invalidate it here. (This is
// reasonably likely to happen when removing a last child in a way
// that doesn't change the size of the parent.)
// This has to sure to invalidate the entire overflow rect; this
// is important in the presence of absolute positioning
aOldFrame->InvalidateFrameForRemoval();
NS_ASSERTION(!aOldFrame->GetPrevContinuation() ||
// exception for nsCSSFrameConstructor::RemoveFloatingFirstLetterFrames
aOldFrame->GetType() == nsGkAtoms::textFrame,
"Must remove first continuation.");
NS_ASSERTION(!(aOldFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW &&
GetPlaceholderFrameFor(aOldFrame)),
"Must call RemoveFrame on placeholder for out-of-flows.");
nsresult rv = NS_OK;
nsIFrame* parentFrame = aOldFrame->GetParent();
if (parentFrame->IsAbsoluteContainer() &&
aListID == parentFrame->GetAbsoluteListID()) {
parentFrame->GetAbsoluteContainingBlock()->
RemoveFrame(parentFrame, aListID, aOldFrame);
} else {
rv = parentFrame->RemoveFrame(aListID, aOldFrame);
}
mIsDestroyingFrames = wasDestroyingFrames;
return rv;
}
//----------------------------------------------------------------------
void
nsFrameManager::NotifyDestroyingFrame(nsIFrame* aFrame)
{
nsIContent* content = aFrame->GetContent();
if (content && content->GetPrimaryFrame() == aFrame) {
ClearAllUndisplayedContentIn(content);
}
}
// Capture state for a given frame.
// Accept a content id here, in some cases we may not have content (scroll position)
void
nsFrameManager::CaptureFrameStateFor(nsIFrame* aFrame,
nsILayoutHistoryState* aState)
{
if (!aFrame || !aState) {
NS_WARNING("null frame, or state");
return;
}
// Only capture state for stateful frames
nsIStatefulFrame* statefulFrame = do_QueryFrame(aFrame);
if (!statefulFrame) {
return;
}
// Capture the state, exit early if we get null (nothing to save)
nsAutoPtr<nsPresState> frameState;
nsresult rv = statefulFrame->SaveState(getter_Transfers(frameState));
if (!frameState) {
return;
}
// Generate the hash key to store the state under
// Exit early if we get empty key
nsAutoCString stateKey;
nsIContent* content = aFrame->GetContent();
nsIDocument* doc = content ? content->GetCurrentDoc() : nullptr;
rv = nsContentUtils::GenerateStateKey(content, doc, stateKey);
if(NS_FAILED(rv) || stateKey.IsEmpty()) {
return;
}
// Store the state. aState owns frameState now.
aState->AddState(stateKey, frameState.forget());
}
void
nsFrameManager::CaptureFrameState(nsIFrame* aFrame,
nsILayoutHistoryState* aState)
{
NS_PRECONDITION(nullptr != aFrame && nullptr != aState, "null parameters passed in");
CaptureFrameStateFor(aFrame, aState);
// Now capture state recursively for the frame hierarchy rooted at aFrame
nsIFrame::ChildListIterator lists(aFrame);
for (; !lists.IsDone(); lists.Next()) {
nsFrameList::Enumerator childFrames(lists.CurrentList());
for (; !childFrames.AtEnd(); childFrames.Next()) {
nsIFrame* child = childFrames.get();
if (child->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
// We'll pick it up when we get to its placeholder
continue;
}
// Make sure to walk through placeholders as needed, so that we
// save state for out-of-flows which may not be our descendants
// themselves but whose placeholders are our descendants.
CaptureFrameState(nsPlaceholderFrame::GetRealFrameFor(child), aState);
}
}
}
// Restore state for a given frame.
// Accept a content id here, in some cases we may not have content (scroll position)
void
nsFrameManager::RestoreFrameStateFor(nsIFrame* aFrame,
nsILayoutHistoryState* aState)
{
if (!aFrame || !aState) {
NS_WARNING("null frame or state");
return;
}
// Only restore state for stateful frames
nsIStatefulFrame* statefulFrame = do_QueryFrame(aFrame);
if (!statefulFrame) {
return;
}
// Generate the hash key the state was stored under
// Exit early if we get empty key
nsIContent* content = aFrame->GetContent();
// If we don't have content, we can't generate a hash
// key and there's probably no state information for us.
if (!content) {
return;
}
nsAutoCString stateKey;
nsIDocument* doc = content->GetCurrentDoc();
nsresult rv = nsContentUtils::GenerateStateKey(content, doc, stateKey);
if (NS_FAILED(rv) || stateKey.IsEmpty()) {
return;
}
// Get the state from the hash
nsPresState* frameState = aState->GetState(stateKey);
if (!frameState) {
return;
}
// Restore it
rv = statefulFrame->RestoreState(frameState);
if (NS_FAILED(rv)) {
return;
}
// If we restore ok, remove the state from the state table
aState->RemoveState(stateKey);
}
void
nsFrameManager::RestoreFrameState(nsIFrame* aFrame,
nsILayoutHistoryState* aState)
{
NS_PRECONDITION(nullptr != aFrame && nullptr != aState, "null parameters passed in");
RestoreFrameStateFor(aFrame, aState);
// Now restore state recursively for the frame hierarchy rooted at aFrame
nsIFrame::ChildListIterator lists(aFrame);
for (; !lists.IsDone(); lists.Next()) {
nsFrameList::Enumerator childFrames(lists.CurrentList());
for (; !childFrames.AtEnd(); childFrames.Next()) {
RestoreFrameState(childFrames.get(), aState);
}
}
}
//----------------------------------------------------------------------
static PLHashNumber
HashKey(void* key)
{
return NS_PTR_TO_INT32(key);
}
static int
CompareKeys(void* key1, void* key2)
{
return key1 == key2;
}
//----------------------------------------------------------------------
nsFrameManagerBase::UndisplayedMap::UndisplayedMap(uint32_t aNumBuckets)
{
MOZ_COUNT_CTOR(nsFrameManagerBase::UndisplayedMap);
mTable = PL_NewHashTable(aNumBuckets, (PLHashFunction)HashKey,
(PLHashComparator)CompareKeys,
(PLHashComparator)nullptr,
nullptr, nullptr);
mLastLookup = nullptr;
}
nsFrameManagerBase::UndisplayedMap::~UndisplayedMap(void)
{
MOZ_COUNT_DTOR(nsFrameManagerBase::UndisplayedMap);
Clear();
PL_HashTableDestroy(mTable);
}
PLHashEntry**
nsFrameManagerBase::UndisplayedMap::GetEntryFor(nsIContent** aParentContent)
{
nsIContent* parentContent = *aParentContent;
if (mLastLookup && (parentContent == (*mLastLookup)->key)) {
return mLastLookup;
}
// In the case of XBL default content, <xbl:children> elements do not get a
// frame causing a mismatch between the content tree and the frame tree.
// |GetEntryFor| is sometimes called with the content tree parent (which may
// be a <xbl:children> element) but the parent in the frame tree would be the
// insertion parent (parent of the <xbl:children> element). Here the children
// elements are normalized to the insertion parent to correct for the mismatch.
if (parentContent && parentContent->IsActiveChildrenElement()) {
parentContent = parentContent->GetParent();
// Change the caller's pointer for the parent content to be the insertion parent.
*aParentContent = parentContent;
}
PLHashNumber hashCode = NS_PTR_TO_INT32(parentContent);
PLHashEntry** entry = PL_HashTableRawLookup(mTable, hashCode, parentContent);
if (*entry) {
mLastLookup = entry;
}
return entry;
}
UndisplayedNode*
nsFrameManagerBase::UndisplayedMap::GetFirstNode(nsIContent* aParentContent)
{
PLHashEntry** entry = GetEntryFor(&aParentContent);
if (*entry) {
return (UndisplayedNode*)((*entry)->value);
}
return nullptr;
}
void
nsFrameManagerBase::UndisplayedMap::AppendNodeFor(UndisplayedNode* aNode,
nsIContent* aParentContent)
{
PLHashEntry** entry = GetEntryFor(&aParentContent);
if (*entry) {
UndisplayedNode* node = (UndisplayedNode*)((*entry)->value);
while (node->mNext) {
if (node->mContent == aNode->mContent) {
// We actually need to check this in optimized builds because
// there are some callers that do this. See bug 118014, bug
// 136704, etc.
NS_NOTREACHED("node in map twice");
delete aNode;
return;
}
node = node->mNext;
}
node->mNext = aNode;
}
else {
PLHashNumber hashCode = NS_PTR_TO_INT32(aParentContent);
PL_HashTableRawAdd(mTable, entry, hashCode, aParentContent, aNode);
mLastLookup = nullptr; // hashtable may have shifted bucket out from under us
}
}
nsresult
nsFrameManagerBase::UndisplayedMap::AddNodeFor(nsIContent* aParentContent,
nsIContent* aChild,
nsStyleContext* aStyle)
{
UndisplayedNode* node = new UndisplayedNode(aChild, aStyle);
AppendNodeFor(node, aParentContent);
return NS_OK;
}
void
nsFrameManagerBase::UndisplayedMap::RemoveNodeFor(nsIContent* aParentContent,
UndisplayedNode* aNode)
{
PLHashEntry** entry = GetEntryFor(&aParentContent);
NS_ASSERTION(*entry, "content not in map");
if (*entry) {
if ((UndisplayedNode*)((*entry)->value) == aNode) { // first node
if (aNode->mNext) {
(*entry)->value = aNode->mNext;
aNode->mNext = nullptr;
}
else {
PL_HashTableRawRemove(mTable, entry, *entry);
mLastLookup = nullptr; // hashtable may have shifted bucket out from under us
}
}
else {
UndisplayedNode* node = (UndisplayedNode*)((*entry)->value);
while (node->mNext) {
if (node->mNext == aNode) {
node->mNext = aNode->mNext;
aNode->mNext = nullptr;
break;
}
node = node->mNext;
}
}
}
delete aNode;
}
void
nsFrameManagerBase::UndisplayedMap::RemoveNodesFor(nsIContent* aParentContent)
{
PLHashEntry** entry = GetEntryFor(&aParentContent);
NS_ASSERTION(entry, "content not in map");
if (*entry) {
UndisplayedNode* node = (UndisplayedNode*)((*entry)->value);
NS_ASSERTION(node, "null node for non-null entry in UndisplayedMap");
delete node;
PL_HashTableRawRemove(mTable, entry, *entry);
mLastLookup = nullptr; // hashtable may have shifted bucket out from under us
}
}
static int
RemoveUndisplayedEntry(PLHashEntry* he, int i, void* arg)
{
UndisplayedNode* node = (UndisplayedNode*)(he->value);
delete node;
// Remove and free this entry and continue enumerating
return HT_ENUMERATE_REMOVE | HT_ENUMERATE_NEXT;
}
void
nsFrameManagerBase::UndisplayedMap::Clear(void)
{
mLastLookup = nullptr;
PL_HashTableEnumerateEntries(mTable, RemoveUndisplayedEntry, 0);
}
uint32_t nsFrameManagerBase::sGlobalGenerationNumber;