Bug 1666881 - Make fission.sessionHistoryInParent require a restart w…

…hen switching. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D91260

docshell/base/BrowsingContext.cpp

@@ -414,7 +414,7 @@ void BrowsingContext::CreateFromIPC(BrowsingContext::IPCInitializer&& aInit,
   context->mCreatedDynamically = aInit.mCreatedDynamically;
   if (context->GetHasSessionHistory()) {
     context->CreateChildSHistory();
-    if (StaticPrefs::fission_sessionHistoryInParent()) {
+    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
       context->GetChildSessionHistory()->SetIndexAndLength(
           aInit.mSessionHistoryIndex, aInit.mSessionHistoryCount, nsID());
     }
@@ -2084,7 +2084,8 @@ BrowsingContext::IPCInitializer BrowsingContext::GetIPCInitializer() {
   init.mUseRemoteSubframes = mUseRemoteSubframes;
   init.mCreatedDynamically = mCreatedDynamically;
   init.mOriginAttributes = mOriginAttributes;
-  if (mChildSessionHistory && StaticPrefs::fission_sessionHistoryInParent()) {
+  if (mChildSessionHistory &&
+      StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     init.mSessionHistoryIndex = mChildSessionHistory->Index();
     init.mSessionHistoryCount = mChildSessionHistory->Count();
   }
@@ -2582,7 +2583,7 @@ void BrowsingContext::InitSessionHistory() {
 }
 
 ChildSHistory* BrowsingContext::GetChildSessionHistory() {
-  if (!StaticPrefs::fission_sessionHistoryInParent()) {
+  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     // For now we're checking that the session history object for the child
     // process is available before returning the ChildSHistory object, because
     // it is the actual implementation that ChildSHistory forwards to. This can
@@ -2640,7 +2641,8 @@ bool BrowsingContext::CanSet(FieldIndex<IDX_PendingInitialization>,
 
 void BrowsingContext::SessionHistoryChanged(int32_t aIndexDelta,
                                             int32_t aLengthDelta) {
-  if (XRE_IsParentProcess() || StaticPrefs::fission_sessionHistoryInParent()) {
+  if (XRE_IsParentProcess() ||
+      StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     // This method is used to test index and length for the session history
     // in child process only.
     return;

docshell/build/nsDocShellModule.cpp

@@ -16,8 +16,6 @@ namespace mozilla {
 // The one time initialization for this module
 nsresult InitDocShellModule() {
   mozilla::dom::BrowsingContext::Init();
-  nsresult rv = nsSHistory::Startup();
-  NS_ENSURE_SUCCESS(rv, rv);
 
   return NS_OK;
 }

docshell/shistory/ChildSHistory.cpp

@@ -33,22 +33,23 @@ void ChildSHistory::SetIsInProcess(bool aIsInProcess) {
     return;
   }
 
-  if (mHistory || StaticPrefs::fission_sessionHistoryInParent()) {
+  if (mHistory || StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     return;
   }
 
   mHistory = new nsSHistory(mBrowsingContext);
 }
 
 int32_t ChildSHistory::Count() {
-  if (StaticPrefs::fission_sessionHistoryInParent() || mAsyncHistoryLength) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ||
+      mAsyncHistoryLength) {
     uint32_t length = mLength;
     for (uint32_t i = 0; i < mPendingSHistoryChanges.Length(); ++i) {
       length += mPendingSHistoryChanges[i].mLengthDelta;
     }
 
     if (mAsyncHistoryLength) {
-      MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent());
+      MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent_AtStartup());
       // XXX The assertion may be too strong here, but it fires only
       //    when the pref is enabled.
       MOZ_ASSERT(mHistory->GetCount() == int32_t(length));
@@ -59,14 +60,15 @@ int32_t ChildSHistory::Count() {
 }
 
 int32_t ChildSHistory::Index() {
-  if (StaticPrefs::fission_sessionHistoryInParent() || mAsyncHistoryLength) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ||
+      mAsyncHistoryLength) {
     uint32_t index = mIndex;
     for (uint32_t i = 0; i < mPendingSHistoryChanges.Length(); ++i) {
       index += mPendingSHistoryChanges[i].mIndexDelta;
     }
 
     if (mAsyncHistoryLength) {
-      MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent());
+      MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent_AtStartup());
       int32_t realIndex;
       mHistory->GetIndex(&realIndex);
       // XXX The assertion may be too strong here, but it fires only
@@ -106,7 +108,7 @@ void ChildSHistory::SetIndexAndLength(uint32_t aIndex, uint32_t aLength,
 }
 
 void ChildSHistory::Reload(uint32_t aReloadFlags, ErrorResult& aRv) {
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     if (XRE_IsParentProcess()) {
       nsISHistory* shistory =
           mBrowsingContext->Canonical()->GetSessionHistory();
@@ -150,7 +152,7 @@ void ChildSHistory::Go(int32_t aOffset, bool aRequireUserInteraction,
     }
 
     // See Bug 1650095.
-    if (StaticPrefs::fission_sessionHistoryInParent()) {
+    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
       break;
     }
 
@@ -188,7 +190,7 @@ void ChildSHistory::AsyncGo(int32_t aOffset, bool aRequireUserInteraction,
 }
 
 void ChildSHistory::GotoIndex(int32_t aIndex, ErrorResult& aRv) {
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     nsCOMPtr<nsISHistory> shistory = mHistory;
     mBrowsingContext->HistoryGo(aIndex, [shistory](int32_t&& aRequestedIndex) {
       // FIXME Should probably only do this for non-fission.
@@ -206,13 +208,13 @@ void ChildSHistory::RemovePendingHistoryNavigations() {
 }
 
 void ChildSHistory::EvictLocalContentViewers() {
-  if (!StaticPrefs::fission_sessionHistoryInParent()) {
+  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     mHistory->EvictAllContentViewers();
   }
 }
 
 nsISHistory* ChildSHistory::GetLegacySHistory(ErrorResult& aError) {
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     aError.ThrowTypeError(
         "legacySHistory is not available with session history in the parent.");
     return nullptr;
@@ -249,7 +251,7 @@ nsISupports* ChildSHistory::GetParentObject() const {
 }
 
 void ChildSHistory::SetAsyncHistoryLength(bool aEnable, ErrorResult& aRv) {
-  if (StaticPrefs::fission_sessionHistoryInParent() || !mHistory) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() || !mHistory) {
     aRv.Throw(NS_ERROR_FAILURE);
     return;
   }

docshell/shistory/nsSHistory.cpp

@@ -238,6 +238,12 @@ nsSHistory::nsSHistory(BrowsingContext* aRootBC)
       mIndex(-1),
       mRequestedIndex(-1),
       mRootDocShellID(aRootBC->GetHistoryID()) {
+  static bool sCalledStartup = false;
+  if (!sCalledStartup) {
+    Startup();
+    sCalledStartup = true;
+  }
+
   // Add this new SHistory object to the list
   gSHistoryList.insertBack(this);
 
@@ -329,7 +335,7 @@ uint32_t nsSHistory::CalcMaxTotalViewers() {
 // static
 void nsSHistory::UpdatePrefs() {
   Preferences::GetInt(PREF_SHISTORY_SIZE, &gHistoryMaxSize);
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     sHistoryMaxTotalViewers = 0;
     return;
   }
@@ -430,7 +436,7 @@ nsresult nsSHistory::WalkHistoryEntries(nsISHEntry* aRootEntry,
         // If the SH pref is on and we are in the parent process, update
         // canonical BC directly
         bool foundChild = false;
-        if (StaticPrefs::fission_sessionHistoryInParent() &&
+        if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() &&
             XRE_IsParentProcess()) {
           if (child->Canonical()->HasHistoryEntry(childEntry)) {
             childBC = child;
@@ -681,7 +687,7 @@ nsresult nsSHistory::SetChildHistoryEntry(nsISHEntry* aEntry,
 void nsSHistory::HandleEntriesToSwapInDocShell(
     mozilla::dom::BrowsingContext* aBC, nsISHEntry* aOldEntry,
     nsISHEntry* aNewEntry) {
-  bool shPref = StaticPrefs::fission_sessionHistoryInParent();
+  bool shPref = StaticPrefs::fission_sessionHistoryInParent_AtStartup();
   if (aBC->IsInProcess() || !shPref) {
     nsDocShell* docshell = static_cast<nsDocShell*>(aBC->GetDocShell());
     if (docshell) {
@@ -1825,7 +1831,7 @@ void nsSHistory::InitiateLoad(nsISHEntry* aFrameEntry,
   // a same-document navigation (see nsDocShell::IsSameDocumentNavigation), so
   // record that here in the LoadingSessionHistoryEntry.
   bool loadingFromActiveEntry;
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     loadingFromActiveEntry =
         aFrameBC->Canonical()->GetActiveSessionHistoryEntry() == aFrameEntry;
   } else {
@@ -1836,7 +1842,7 @@ void nsSHistory::InitiateLoad(nsISHEntry* aFrameEntry,
   loadState->SetLoadIsFromSessionHistory(mRequestedIndex, Length(),
                                          loadingFromActiveEntry);
 
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     nsCOMPtr<SessionHistoryEntry> she = do_QueryInterface(aFrameEntry);
     aFrameBC->Canonical()->AddLoadingSessionHistoryEntry(
         loadState->GetLoadingSessionHistoryInfo()->mLoadId, she);
@@ -1861,7 +1867,8 @@ void nsSHistory::InitiateLoad(nsISHEntry* aFrameEntry,
 NS_IMETHODIMP
 nsSHistory::CreateEntry(nsISHEntry** aEntry) {
   nsCOMPtr<nsISHEntry> entry;
-  if (XRE_IsParentProcess() && StaticPrefs::fission_sessionHistoryInParent()) {
+  if (XRE_IsParentProcess() &&
+      StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     entry = new SessionHistoryEntry();
   } else {
     entry = new nsSHEntry();

docshell/shistory/nsSHistory.h

@@ -70,7 +70,7 @@ class nsSHistory : public mozilla::LinkedListElement<nsSHistory>,
   NS_DECL_ISUPPORTS
   NS_DECL_NSISHISTORY
 
-  // One time initialization method called upon docshell module construction
+  // One time initialization method
   static nsresult Startup();
   static void Shutdown();
   static void UpdatePrefs();

dom/base/nsCCUncollectableMarker.cpp

@@ -251,7 +251,8 @@ void MarkDocShell(nsIDocShellTreeItem* aNode, bool aCleanupJS) {
   nsISHistory* legacyHistory =
       history ? history->GetLegacySHistory(ignore) : nullptr;
   if (legacyHistory) {
-    MOZ_DIAGNOSTIC_ASSERT(!StaticPrefs::fission_sessionHistoryInParent());
+    MOZ_DIAGNOSTIC_ASSERT(
+        !StaticPrefs::fission_sessionHistoryInParent_AtStartup());
     int32_t historyCount = history->Count();
     for (int32_t i = 0; i < historyCount; ++i) {
       nsCOMPtr<nsISHEntry> shEntry;

dom/base/nsFrameLoader.cpp

@@ -1881,7 +1881,7 @@ void nsFrameLoader::StartDestroy(bool aForProcessSwitch) {
       RefPtr<ChildSHistory> childSHistory =
           browsingContext->Top()->GetChildSessionHistory();
       if (childSHistory) {
-        if (StaticPrefs::fission_sessionHistoryInParent()) {
+        if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
           browsingContext->RemoveFromSessionHistory();
         } else {
           AutoTArray<nsID, 16> ids({browsingContext->GetHistoryID()});

dom/base/nsGlobalWindowOuter.cpp

@@ -6348,7 +6348,7 @@ bool nsGlobalWindowOuter::IsOnlyTopLevelDocumentInSHistory() {
   // Disabled since IsFrame() is buggy in Fission
   // MOZ_ASSERT(mBrowsingContext->IsTop());
 
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     return mBrowsingContext->GetIsSingleToplevelInHistory();
   }
 

dom/ipc/BrowserChild.cpp

@@ -3450,7 +3450,7 @@ nsresult BrowserChild::CanCancelContentJS(
 
   // If we have session history in the parent we've already performed
   // the checks following, so we can return early.
-  if (StaticPrefs::fission_sessionHistoryInParent()) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     *aCanCancel = true;
     return NS_OK;
   }

dom/ipc/BrowserParent.cpp

@@ -3519,7 +3519,7 @@ bool BrowserParent::CanCancelContentJS(
     nsIURI* aNavigationURI) const {
   // Pre-checking if we can cancel content js in the parent is only
   // supported when session history in the parent is enabled.
-  if (!StaticPrefs::fission_sessionHistoryInParent()) {
+  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     // If session history in the parent isn't enabled, this check will
     // be fully done in BrowserChild::CanCancelContentJS
     return true;

layout/base/nsDocumentViewer.cpp

@@ -2060,7 +2060,7 @@ nsDocumentViewer::Show(void) {
       treeItem->GetInProcessSameTypeRootTreeItem(getter_AddRefs(root));
       nsCOMPtr<nsIWebNavigation> webNav = do_QueryInterface(root);
       RefPtr<ChildSHistory> history = webNav->GetSessionHistory();
-      if (!StaticPrefs::fission_sessionHistoryInParent() && history) {
+      if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup() && history) {
         int32_t prevIndex, loadedIndex;
         nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(treeItem);
         docShell->GetPreviousEntryIndex(&prevIndex);

modules/libpref/init/StaticPrefList.yaml

@@ -3590,7 +3590,7 @@
 - name: fission.sessionHistoryInParent
   type: bool
   value: false
-  mirror: always
+  mirror: once
 
 # Allow renaming of process names to the origin on nightly
 # Setting this pref creates a privacy leak, but helps greatly with

netwerk/ipc/DocumentLoadListener.cpp

@@ -626,7 +626,8 @@ auto DocumentLoadListener::Open(nsDocShellLoadState* aLoadState,
   mSrcdocData = aLoadState->SrcdocData();
   mBaseURI = aLoadState->BaseURI();
   mOriginalUriString = aLoadState->GetOriginalURIString();
-  if (documentContext && StaticPrefs::fission_sessionHistoryInParent()) {
+  if (documentContext &&
+      StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     // It's hard to know at this point whether session history will be enabled
     // in the browsing context, so we always create an entry for a load here.
     mLoadingSessionHistoryInfo =

netwerk/ipc/ParentProcessDocumentChannel.cpp

@@ -69,7 +69,8 @@ ParentProcessDocumentChannel::RedirectToRealChannel(
   mStreamFilterEndpoints = std::move(aStreamFilterEndpoints);
 
   if (mDocumentLoadListener->IsDocumentLoad() &&
-      StaticPrefs::fission_sessionHistoryInParent() && GetDocShell()) {
+      StaticPrefs::fission_sessionHistoryInParent_AtStartup() &&
+      GetDocShell()) {
     GetDocShell()->SetLoadingSessionHistoryInfo(
         *mDocumentLoadListener->GetLoadingSessionHistoryInfo());
   }

toolkit/components/sessionstore/SessionStoreListener.cpp

@@ -46,7 +46,6 @@ ContentSessionStore::ContentSessionStore(nsIDocShell* aDocShell)
       mFormDataChanged(NO_CHANGE),
       mStorageStatus(NO_STORAGE),
       mDocCapChanged(false),
-      mSHistoryInParent(StaticPrefs::fission_sessionHistoryInParent()),
       mSHistoryChanged(false),
       mSHistoryChangedFromParent(false) {
   MOZ_ASSERT(mDocShell);
@@ -117,6 +116,16 @@ void ContentSessionStore::ResetStorageChanges() {
   mValues.Clear();
 }
 
+void ContentSessionStore::SetSHistoryChanged() {
+  mSHistoryChanged = StaticPrefs::fission_sessionHistoryInParent_AtStartup();
+}
+
+// Request "collect sessionHistory" from the parent process
+void ContentSessionStore::SetSHistoryFromParentChanged() {
+  mSHistoryChangedFromParent =
+      StaticPrefs::fission_sessionHistoryInParent_AtStartup();
+}
+
 void ContentSessionStore::OnDocumentStart() {
   mScrollChanged = PAGELOADEDSTART;
   mFormDataChanged = PAGELOADEDSTART;
@@ -128,7 +137,7 @@ void ContentSessionStore::OnDocumentStart() {
 
   SetFullStorageNeeded();
 
-  if (mSHistoryInParent) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     mSHistoryChanged = true;
   }
 }
@@ -137,7 +146,7 @@ void ContentSessionStore::OnDocumentEnd() {
   mScrollChanged = WITH_CHANGE;
   SetFullStorageNeeded();
 
-  if (mSHistoryInParent) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     mSHistoryChanged = true;
   }
 }
@@ -168,8 +177,7 @@ TabListener::TabListener(nsIDocShell* aDocShell, Element* aElement)
       mUpdatedTimer(nullptr),
       mTimeoutDisabled(false),
       mUpdateInterval(15000),
-      mEpoch(0),
-      mSHistoryInParent(StaticPrefs::fission_sessionHistoryInParent()) {
+      mEpoch(0) {
   MOZ_ASSERT(mDocShell);
 }
 
@@ -219,7 +227,7 @@ nsresult TabListener::Init() {
   eventTarget->AddSystemEventListener(u"mozvisualscroll"_ns, this, false);
   eventTarget->AddSystemEventListener(u"input"_ns, this, false);
 
-  if (mSHistoryInParent) {
+  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
     eventTarget->AddSystemEventListener(u"DOMTitleChanged"_ns, this, false);
   }
 
@@ -809,7 +817,7 @@ void TabListener::RemoveListeners() {
         eventTarget->RemoveSystemEventListener(u"mozvisualscroll"_ns, this,
                                                false);
         eventTarget->RemoveSystemEventListener(u"input"_ns, this, false);
-        if (mSHistoryInParent) {
+        if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
           eventTarget->RemoveSystemEventListener(u"DOMTitleChanged"_ns, this,
                                                  false);
         }