Bug 1500948 - Expose BrowsingContext on nsFrameLoader objects, r=farre

This should make BrowsingContext more usable by making it much easier to obtain
for a given frame or browser. BrowsingContext and nsFrameLoader should have
the same lifetime.

Differential Revision: https://phabricator.services.mozilla.com/D9395

dom/base/nsFrameLoader.cpp

@@ -100,6 +100,7 @@
 #include "mozilla/dom/PromiseNativeHandler.h"
 #include "mozilla/dom/ParentSHistory.h"
 #include "mozilla/dom/ChildSHistory.h"
+#include "mozilla/dom/ChromeBrowsingContext.h"
 
 #include "mozilla/dom/HTMLBodyElement.h"
 
@@ -3022,6 +3023,16 @@ already_AddRefed<nsILoadContext> nsFrameLoader::LoadContext() {
   return loadContext.forget();
 }
 
+already_AddRefed<BrowsingContext> nsFrameLoader::GetBrowsingContext() {
+  RefPtr<BrowsingContext> browsingContext;
+  if (IsRemoteFrame() && (mRemoteBrowser || TryRemoteBrowser())) {
+    browsingContext = mRemoteBrowser->GetBrowsingContext();
+  } else if (GetDocShell(IgnoreErrors())) {
+    browsingContext = nsDocShell::Cast(mDocShell)->GetBrowsingContext();
+  }
+  return browsingContext.forget();
+}
+
 void nsFrameLoader::InitializeBrowserAPI() {
   if (!OwnerIsMozBrowserFrame()) {
     return;

dom/base/nsFrameLoader.h

@@ -48,6 +48,7 @@ namespace mozilla {
 class OriginAttributes;
 
 namespace dom {
+class BrowsingContext;
 class ChromeMessageSender;
 class ContentParent;
 class InProcessTabChildMessageManager;
@@ -123,6 +124,8 @@ class nsFrameLoader final : public nsStubMutationObserver,
 
   already_AddRefed<nsILoadContext> LoadContext();
 
+  already_AddRefed<mozilla::dom::BrowsingContext> GetBrowsingContext();
+
   /**
    * Start loading the frame. This method figures out what to load
    * from the owner content in the frame loader.

dom/ipc/PBrowser.ipdl

@@ -588,6 +588,8 @@ parent:
     sync SetPrefersReducedMotionOverrideForTest(bool aValue);
     sync ResetPrefersReducedMotionOverrideForTest();
 
+    async RootBrowsingContext(BrowsingContextId aId);
+
 child:
     /**
      * Notify the remote browser that it has been Show()n on this

dom/ipc/TabChild.cpp

@@ -538,6 +538,11 @@ nsresult TabChild::Init(mozIDOMWindowProxy* aParent) {
   loadContext->SetRemoteTabs(mChromeFlags &
                              nsIWebBrowserChrome::CHROME_REMOTE_WINDOW);
 
+  // Send our browsing context to the parent process.
+  RefPtr<BrowsingContext> browsingContext =
+      nsDocShell::Cast(docShell)->GetBrowsingContext();
+  SendRootBrowsingContext(BrowsingContextId(browsingContext->Id()));
+
   // Few lines before, baseWindow->Create() will end up creating a new
   // window root in nsGlobalWindow::SetDocShell.
   // Then this chrome event handler, will be inherited to inner windows.

dom/ipc/TabParent.cpp

@@ -101,6 +101,7 @@
 #include "nsString.h"
 #include "IHistory.h"
 #include "mozilla/dom/WindowGlobalParent.h"
+#include "mozilla/dom/ChromeBrowsingContext.h"
 
 #ifdef XP_WIN
 #include "mozilla/plugins/PluginWidgetParent.h"
@@ -3390,6 +3391,14 @@ mozilla::ipc::IPCResult TabParent::RecvGetSystemFont(nsCString* aFontName) {
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult TabParent::RecvRootBrowsingContext(
+    const BrowsingContextId& aId) {
+  MOZ_ASSERT(!mBrowsingContext, "May only set browsing context once!");
+  mBrowsingContext = ChromeBrowsingContext::Get(aId);
+  MOZ_ASSERT(mBrowsingContext, "Invalid ID!");
+  return IPC_OK();
+}
+
 NS_IMETHODIMP
 FakeChannel::OnAuthAvailable(nsISupports* aContext,
                              nsIAuthInformation* aAuthInfo) {

dom/ipc/TabParent.h

@@ -67,6 +67,7 @@ class DataSourceSurface;
 
 namespace dom {
 
+class ChromeBrowsingContext;
 class ClonedMessageData;
 class nsIContentParent;
 class Element;
@@ -125,6 +126,8 @@ class TabParent final : public PBrowserParent,
 
   nsIXULBrowserWindow* GetXULBrowserWindow();
 
+  ChromeBrowsingContext* GetBrowsingContext() { return mBrowsingContext; }
+
   void Destroy();
 
   void RemoveWindowListeners();
@@ -584,6 +587,9 @@ class TabParent final : public PBrowserParent,
   virtual mozilla::ipc::IPCResult RecvShowCanvasPermissionPrompt(
       const nsCString& aFirstPartyURI) override;
 
+  virtual mozilla::ipc::IPCResult RecvRootBrowsingContext(
+      const BrowsingContextId& aId) override;
+
   mozilla::ipc::IPCResult RecvSetSystemFont(
       const nsCString& aFontName) override;
   mozilla::ipc::IPCResult RecvGetSystemFont(nsCString* aFontName) override;
@@ -661,6 +667,9 @@ class TabParent final : public PBrowserParent,
   // dispatch message manager messages during this time.
   RefPtr<nsFrameLoader> mFrameLoader;
 
+  // The root browsing context loaded in this TabParent.
+  RefPtr<ChromeBrowsingContext> mBrowsingContext;
+
   TabId mTabId;
 
   // When loading a new tab or window via window.open, the child is

dom/webidl/FrameLoader.webidl

@@ -33,6 +33,12 @@ interface FrameLoader {
    */
   readonly attribute LoadContext loadContext;
 
+  /**
+   * Get the root BrowsingContext within the frame.
+   * This may be null immediately after creating a remote frame.
+   */
+  readonly attribute BrowsingContext? browsingContext;
+
   /**
    * Get the ParentSHistory for the nsFrameLoader. May return null if this
    * frameloader is not for a toplevel frame.