Bug 1540839 - Add ability to preserve browsing contexts between FrameLoaders; r=nika

When changing processes and therefore destroying/rebuilding
frameloaders, add ability to keep the browsing context around and add
it to the new frameloader.

Differential Revision: https://phabricator.services.mozilla.com/D26267

docshell/base/nsDocShell.cpp

@@ -385,7 +385,8 @@ nsDocShell::nsDocShell(BrowsingContext* aBrowsingContext)
       mHasLoadedNonBlankURI(false),
       mBlankTiming(false),
       mTitleValidForCurrentURI(false),
-      mIsFrame(false) {
+      mIsFrame(false),
+      mSkipBrowsingContextDetachOnDestroy(false) {
   mHistoryID.m0 = 0;
   mHistoryID.m1 = 0;
   mHistoryID.m2 = 0;
@@ -5036,7 +5037,11 @@ nsDocShell::Destroy() {
     mSessionHistory = nullptr;
   }
 
-  mBrowsingContext->Detach();
+  // This will be skipped in cases where we want to preserve the browsing
+  // context between loads.
+  if (!mSkipBrowsingContextDetachOnDestroy) {
+    mBrowsingContext->Detach();
+  }
 
   SetTreeOwner(nullptr);
 

docshell/base/nsDocShell.h

@@ -405,6 +405,10 @@ class nsDocShell final : public nsDocLoader,
   // Clear the document's storage access flag if needed.
   void MaybeClearStorageAccessFlag();
 
+  void SkipBrowsingContextDetach() {
+    mSkipBrowsingContextDetachOnDestroy = true;
+  }
+
  private:  // member functions
   friend class nsDSURIContentListener;
   friend class FramingChecker;
@@ -1205,6 +1209,11 @@ class nsDocShell final : public nsDocLoader,
   bool mTitleValidForCurrentURI : 1;
 
   bool mIsFrame : 1;
+
+  // If mSkipBrowsingContextDetachOnDestroy is set to true, then when the
+  // docshell is destroyed, the browsing context will not be detached. This is
+  // for cases where we want to preserve the BC for future use.
+  bool mSkipBrowsingContextDetachOnDestroy : 1;
 };
 
 #endif /* nsDocShell_h__ */

dom/base/nsFrameLoader.cpp

@@ -364,7 +364,7 @@ nsFrameLoader* nsFrameLoader::Create(Element* aOwner, BrowsingContext* aOpener,
 
 /* static */
 nsFrameLoader* nsFrameLoader::Create(
-    mozilla::dom::Element* aOwner,
+    mozilla::dom::Element* aOwner, BrowsingContext* aPreservedBrowsingContext,
     const mozilla::dom::RemotenessOptions& aOptions) {
   NS_ENSURE_TRUE(aOwner, nullptr);
   // This version of Create is only called for Remoteness updates, so we can
@@ -381,7 +381,12 @@ nsFrameLoader* nsFrameLoader::Create(
   if (hasOpener) {
     opener = aOptions.mOpener.Value().Value().get();
   }
-  RefPtr<BrowsingContext> context = CreateBrowsingContext(aOwner, opener);
+  RefPtr<BrowsingContext> context;
+  if (aPreservedBrowsingContext) {
+    context = aPreservedBrowsingContext;
+  } else {
+    context = CreateBrowsingContext(aOwner, opener);
+  }
   NS_ENSURE_TRUE(context, nullptr);
   return new nsFrameLoader(aOwner, context, aOptions);
 }
@@ -3490,3 +3495,22 @@ JSObject* nsFrameLoader::WrapObject(JSContext* cx,
   FrameLoader_Binding::Wrap(cx, this, this, aGivenProto, &result);
   return result;
 }
+
+void nsFrameLoader::SkipBrowsingContextDetach() {
+  if (IsRemoteFrame()) {
+    // OOP Browser - Go directly over Browser Parent
+    if (mBrowserParent) {
+      Unused << mBrowserParent->SendSkipBrowsingContextDetach();
+    }
+    // OOP IFrame - Through Browser Bridge Parent, set on browser child
+    else if (mBrowserBridgeChild) {
+      Unused << mBrowserBridgeChild->SendSkipBrowsingContextDetach();
+    }
+    return;
+  }
+
+  // In process
+  RefPtr<nsDocShell> docshell = GetDocShell();
+  MOZ_ASSERT(docshell);
+  docshell->SkipBrowsingContextDetach();
+}

dom/base/nsFrameLoader.h

@@ -95,6 +95,7 @@ class nsFrameLoader final : public nsStubMutationObserver,
   typedef mozilla::dom::PBrowserParent PBrowserParent;
   typedef mozilla::dom::Document Document;
   typedef mozilla::dom::BrowserParent BrowserParent;
+  typedef mozilla::dom::BrowsingContext BrowsingContext;
   typedef mozilla::layout::RenderFrame RenderFrame;
 
  public:
@@ -106,6 +107,7 @@ class nsFrameLoader final : public nsStubMutationObserver,
   // Called by nsFrameLoaderOwner::ChangeRemoteness when switching out
   // FrameLoaders.
   static nsFrameLoader* Create(mozilla::dom::Element* aOwner,
+                               BrowsingContext* aPreservedBrowsingContext,
                                const mozilla::dom::RemotenessOptions& aOptions);
 
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_FRAMELOADER_IID)
@@ -385,6 +387,8 @@ class nsFrameLoader final : public nsStubMutationObserver,
   virtual JSObject* WrapObject(JSContext* cx,
                                JS::Handle<JSObject*> aGivenProto) override;
 
+  void SkipBrowsingContextDetach();
+
  private:
   nsFrameLoader(mozilla::dom::Element* aOwner,
                 mozilla::dom::BrowsingContext* aBrowsingContext,

dom/base/nsFrameLoaderOwner.cpp

@@ -32,8 +32,14 @@ nsFrameLoaderOwner::GetBrowsingContext() {
 
 void nsFrameLoaderOwner::ChangeRemoteness(
     const mozilla::dom::RemotenessOptions& aOptions, mozilla::ErrorResult& rv) {
+  RefPtr<mozilla::dom::BrowsingContext> bc;
   // If we already have a Frameloader, destroy it.
   if (mFrameLoader) {
+    bc = mFrameLoader->GetBrowsingContext();
+
+    // TODO pass in Cross-Origin-Load-Policy rules
+    mFrameLoader->SkipBrowsingContextDetach();
+
     mFrameLoader->Destroy();
     mFrameLoader = nullptr;
   }
@@ -43,7 +49,8 @@ void nsFrameLoaderOwner::ChangeRemoteness(
   // owner.
   RefPtr<Element> owner = do_QueryObject(this);
   MOZ_ASSERT(owner);
-  mFrameLoader = nsFrameLoader::Create(owner, aOptions);
+  mFrameLoader = nsFrameLoader::Create(owner, bc, aOptions);
+
   if (NS_WARN_IF(!mFrameLoader)) {
     return;
   }
@@ -70,9 +77,8 @@ void nsFrameLoaderOwner::ChangeRemoteness(
   // FrameLoader, fire an event to act like we've recreated ourselves, similar
   // to what XULFrameElement does after rebinding to the tree.
   // ChromeOnlyDispatch is turns on to make sure this isn't fired into content.
-  (new mozilla::AsyncEventDispatcher(owner,
-                                     NS_LITERAL_STRING("XULFrameLoaderCreated"),
-                                     mozilla::CanBubble::eYes,
-                                     mozilla::ChromeOnlyDispatch::eYes))
+  (new mozilla::AsyncEventDispatcher(
+       owner, NS_LITERAL_STRING("XULFrameLoaderCreated"),
+       mozilla::CanBubble::eYes, mozilla::ChromeOnlyDispatch::eYes))
       ->RunDOMEventWhenSafe();
 }

dom/ipc/BrowserBridgeParent.cpp

@@ -182,6 +182,11 @@ IPCResult BrowserBridgeParent::RecvDispatchSynthesizedMouseEvent(
   return IPC_OK();
 }
 
+IPCResult BrowserBridgeParent::RecvSkipBrowsingContextDetach() {
+  mBrowserParent->SkipBrowsingContextDetach();
+  return IPC_OK();
+}
+
 IPCResult BrowserBridgeParent::RecvActivate() {
   mBrowserParent->Activate();
   return IPC_OK();

dom/ipc/BrowserBridgeParent.h

@@ -59,6 +59,8 @@ class BrowserBridgeParent : public PBrowserBridgeParent {
   mozilla::ipc::IPCResult RecvDispatchSynthesizedMouseEvent(
       const WidgetMouseEvent& aEvent);
 
+  mozilla::ipc::IPCResult RecvSkipBrowsingContextDetach();
+
   mozilla::ipc::IPCResult RecvActivate();
 
   mozilla::ipc::IPCResult RecvDeactivate();

dom/ipc/BrowserChild.cpp

@@ -1052,6 +1052,17 @@ BrowserChild::~BrowserChild() {
   mozilla::DropJSObjects(this);
 }
 
+mozilla::ipc::IPCResult BrowserChild::RecvSkipBrowsingContextDetach() {
+  nsCOMPtr<nsIDocShell> docShell = do_GetInterface(WebNavigation());
+  if (!docShell) {
+    return IPC_OK();
+  }
+  RefPtr<nsDocShell> docshell = nsDocShell::Cast(docShell);
+  MOZ_ASSERT(docshell);
+  docshell->SkipBrowsingContextDetach();
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult BrowserChild::RecvLoadURL(const nsCString& aURI,
                                                   const ShowInfo& aInfo) {
   if (!mDidLoadURLInit) {

dom/ipc/BrowserChild.h

@@ -555,6 +555,7 @@ class BrowserChild final : public BrowserChildBase,
   mozilla::ipc::IPCResult RecvUpdateNativeWindowHandle(
       const uintptr_t& aNewHandle);
 
+  virtual mozilla::ipc::IPCResult RecvSkipBrowsingContextDetach() override;
   /**
    * Native widget remoting protocol for use with windowed plugins with e10s.
    */

dom/ipc/BrowserParent.cpp

@@ -3744,6 +3744,12 @@ BrowserParent::StopApzAutoscroll(nsViewID aScrollId, uint32_t aPresShellId) {
   return NS_OK;
 }
 
+void BrowserParent::SkipBrowsingContextDetach() {
+  RefPtr<nsFrameLoader> fl = GetFrameLoader();
+  MOZ_ASSERT(fl);
+  fl->SkipBrowsingContextDetach();
+}
+
 mozilla::ipc::IPCResult BrowserParent::RecvLookUpDictionary(
     const nsString& aText, nsTArray<FontRange>&& aFontRangeArray,
     const bool& aIsVertical, const LayoutDeviceIntPoint& aPoint) {

dom/ipc/BrowserParent.h

@@ -678,6 +678,8 @@ class BrowserParent final : public PBrowserParent,
 
   void NavigateByKey(bool aForward, bool aForDocumentNavigation);
 
+  void SkipBrowsingContextDetach();
+
  protected:
   bool ReceiveMessage(
       const nsString& aMessage, bool aSync, ipc::StructuredCloneData* aData,

dom/ipc/PBrowser.ipdl

@@ -948,6 +948,7 @@ child:
      */
     async GetContentBlockingLog() returns(nsCString log, bool success);
 
+    async SkipBrowsingContextDetach();
 parent:
     /** Records a history visit. */
     async VisitURI(URIParams aURI, URIParams? aLastVisitedURI,

dom/ipc/PBrowserBridge.ipdl

@@ -74,6 +74,8 @@ parent:
   async Deactivate();
 
   async SetIsUnderHiddenEmbedderElement(bool aIsUnderHiddenEmbedderElement);
+
+  async SkipBrowsingContextDetach();
 };
 
 }  // namespace dom

dom/ipc/WindowGlobalParent.cpp

@@ -82,10 +82,6 @@ void WindowGlobalParent::Init(const WindowGlobalInit& aInit) {
   mBrowsingContext = CanonicalBrowsingContext::Cast(aInit.browsingContext());
   MOZ_ASSERT(mBrowsingContext);
 
-  // XXX(nika): This won't be the case soon, but for now this is a good
-  // assertion as we can't switch processes. We should relax this eventually.
-  MOZ_ASSERT(mBrowsingContext->IsOwnedByProcess(processId));
-
   // Attach ourself to the browsing context.
   mBrowsingContext->RegisterWindowGlobal(this);