Bug 1481238 - Create WebIDL interface for BrowsingContext. r=peterv

Expose Chrome only WebIDL to interface with BrowsingContext from
script. The API consists of parent, firstChild and nextSibling
attributes for BrowsingContext, and the browsingContext attribute for
Window.

--HG--
extra : rebase_source : 772d25e8b4e5526453545ddb2b1607845f3b65ea

docshell/base/BrowsingContext.cpp

@@ -6,6 +6,7 @@
 
 #include "BrowsingContext.h"
 
+#include "mozilla/dom/BrowsingContextBinding.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/ClearOnShutdown.h"
@@ -131,8 +132,8 @@ BrowsingContext::Attach(BrowsingContext* aParent)
   MOZ_LOG(GetLog(),
           LogLevel::Debug,
           ("%s: %s 0x%08" PRIx64 " to 0x%08" PRIx64,
-           wasCached ? "Re-connecting" : "Connecting",
            XRE_IsParentProcess() ? "Parent" : "Child",
+           wasCached ? "Re-connecting" : "Connecting",
            Id(),
            aParent ? aParent->Id() : 0));
 
@@ -230,6 +231,22 @@ BrowsingContext::OwnerProcessId() const
   return mProcessId.value();
 }
 
+void
+BrowsingContext::GetChildren(nsTArray<RefPtr<BrowsingContext>>& aChildren)
+{
+  for (BrowsingContext* context : mChildren) {
+    aChildren.AppendElement(context);
+  }
+}
+
+/* static */ void
+BrowsingContext::GetRootBrowsingContexts(nsTArray<RefPtr<BrowsingContext>>& aBrowsingContexts)
+{
+  for (BrowsingContext* context : *sRootBrowsingContexts) {
+    aBrowsingContexts.AppendElement(context);
+  }
+}
+
 BrowsingContext::~BrowsingContext()
 {
   MOZ_DIAGNOSTIC_ASSERT(!isInList());
@@ -239,6 +256,19 @@ BrowsingContext::~BrowsingContext()
   }
 }
 
+nsISupports*
+BrowsingContext::GetParentObject() const
+{
+  return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
+}
+
+JSObject*
+BrowsingContext::WrapObject(JSContext* aCx,
+                            JS::Handle<JSObject*> aGivenProto)
+{
+  return BrowsingContext_Binding::Wrap(aCx, this, aGivenProto);
+}
+
 static void
 ImplCycleCollectionUnlink(BrowsingContext::Children& aField)
 {
@@ -257,7 +287,7 @@ ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
   }
 }
 
-NS_IMPL_CYCLE_COLLECTION(BrowsingContext, mDocShell, mChildren)
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(BrowsingContext, mDocShell, mChildren)
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(BrowsingContext, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(BrowsingContext, Release)
 

docshell/base/BrowsingContext.h

@@ -14,6 +14,8 @@
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsString.h"
+#include "nsTArray.h"
+#include "nsWrapperCache.h"
 
 class nsIDocShell;
 
@@ -36,7 +38,8 @@ namespace dom {
 // BrowsingContext tree for a tab, in both the parent and the child
 // process.
 class BrowsingContext
-  : public SupportsWeakPtr<BrowsingContext>
+  : public nsWrapperCache
+  , public SupportsWeakPtr<BrowsingContext>
   , public LinkedListElement<RefPtr<BrowsingContext>>
 {
 public:
@@ -81,16 +84,28 @@ public:
   uint64_t OwnerProcessId() const;
   bool IsOwnedByProcess() const { return mProcessId.isSome(); }
 
-  BrowsingContext* Parent() const { return mParent; }
+  already_AddRefed<BrowsingContext> GetParent()
+  {
+    return do_AddRef(mParent.get());
+  }
+
+  void GetChildren(nsTArray<RefPtr<BrowsingContext>>& aChildren);
+
+  static void GetRootBrowsingContexts(
+    nsTArray<RefPtr<BrowsingContext>>& aBrowsingContexts);
+
+  nsISupports* GetParentObject() const;
+  virtual JSObject* WrapObject(JSContext* aCx,
+                               JS::Handle<JSObject*> aGivenProto) override;
 
   MOZ_DECLARE_WEAKREFERENCE_TYPENAME(BrowsingContext)
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(BrowsingContext)
-  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(BrowsingContext)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(BrowsingContext)
 
   using Children = AutoCleanLinkedList<RefPtr<BrowsingContext>>;
 
 private:
-  ~BrowsingContext();
+  virtual ~BrowsingContext();
 
   const uint64_t mBrowsingContextId;
 

docshell/base/nsDocShell.cpp

@@ -14335,6 +14335,13 @@ nsDocShell::GetBrowsingContext() const
   return browsingContext.forget();
 }
 
+NS_IMETHODIMP
+nsDocShell::GetBrowsingContext(BrowsingContext** aBrowsingContext)
+{
+  *aBrowsingContext = do_AddRef(mBrowsingContext).take();
+  return NS_OK;
+}
+
 void
 nsIDocShell::AttachBrowsingContext(nsIDocShell* aParentDocShell)
 {

docshell/base/nsIDocShell.idl

@@ -65,6 +65,7 @@ interface nsILoadURIDelegate;
 native TabChildRef(already_AddRefed<nsITabChild>);
 native nsDocShellLoadInfoPtr(nsDocShellLoadInfo*);
 
+webidl BrowsingContext;
 webidl ContentFrameMessageManager;
 webidl EventTarget;
 
@@ -1190,6 +1191,11 @@ interface nsIDocShell : nsIDocShellTreeItem
   void DetachBrowsingContext();
 %}
 
+  /**
+   * BrowsingContext associated with the DocShell.
+   */
+  readonly attribute BrowsingContext browsingContext;
+
   /**
    * Allowed CSS display modes. This needs to be kept in
    * sync with similar values in nsStyleConsts.h

dom/base/ChromeUtils.cpp

@@ -17,6 +17,7 @@
 #include "mozilla/PerformanceMetricsCollector.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/TimeStamp.h"
+#include "mozilla/dom/BrowsingContext.h"
 #include "mozilla/dom/ContentParent.h"
 #include "mozilla/dom/IdleDeadline.h"
 #include "mozilla/dom/UnionTypes.h"
@@ -781,5 +782,12 @@ ChromeUtils::RequestIOActivity(GlobalObject& aGlobal, ErrorResult& aRv)
   return domPromise.forget();
 }
 
+/* static */ void
+ChromeUtils::GetRootBrowsingContexts(GlobalObject& aGlobal,
+                                     nsTArray<RefPtr<BrowsingContext>>& aBrowsingContexts)
+{
+  BrowsingContext::GetRootBrowsingContexts(aBrowsingContexts);
+}
+
 } // namespace dom
 } // namespace mozilla

dom/base/ChromeUtils.h

@@ -21,6 +21,7 @@ class HeapSnapshot;
 namespace dom {
 
 class ArrayBufferViewOrArrayBuffer;
+class BrowsingContext;
 class IdleRequestCallback;
 struct IdleRequestOptions;
 class MozQueryInterface;
@@ -187,6 +188,10 @@ public:
 
   static already_AddRefed<Promise>
   RequestIOActivity(GlobalObject& aGlobal, ErrorResult& aRv);
+
+  static void
+  GetRootBrowsingContexts(GlobalObject& aGlobal,
+                          nsTArray<RefPtr<BrowsingContext>>& aBrowsingContexts);
 };
 
 } // namespace dom

dom/chrome-webidl/BrowsingContext.webidl

@@ -0,0 +1,13 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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/. */
+
+[Exposed=(Window, System), ChromeOnly]
+interface BrowsingContext {
+  readonly attribute BrowsingContext? parent;
+
+  sequence<BrowsingContext> getChildren();
+
+  readonly attribute unsigned long long id;
+};

dom/chrome-webidl/ChromeUtils.webidl

@@ -355,6 +355,9 @@ partial namespace ChromeUtils {
   */
   [Throws]
   Promise<sequence<IOActivityDataDictionary>> requestIOActivity();
+
+  [ChromeOnly]
+  sequence<BrowsingContext> getRootBrowsingContexts();
 };
 
 /**

dom/chrome-webidl/moz.build

@@ -30,6 +30,7 @@ PREPROCESSED_WEBIDL_FILES = [
 ]
 
 WEBIDL_FILES = [
+    'BrowsingContext.webidl',
     'ChannelWrapper.webidl',
     'DominatorTree.webidl',
     'HeapSnapshot.webidl',