Bug 1543298 part 3: For out-of-process iframes, send the embedded document accessible's COM proxy to the embedder. r=eeejay

This will be later exposed as a child of the embedder OuterDocAccessible.

Differential Revision: https://phabricator.services.mozilla.com/D32280

--HG--
extra : moz-landing-system : lando

accessible/ipc/DocAccessibleParent.cpp

@@ -536,6 +536,30 @@ ipc::IPCResult DocAccessibleParent::AddChildDoc(DocAccessibleParent* aChildDoc,
     ProxyCreated(aChildDoc, Interfaces::DOCUMENT | Interfaces::HYPERTEXT);
   }
 
+#if defined(XP_WIN)
+  auto embeddedBrowser = static_cast<dom::BrowserParent*>(aChildDoc->Manager());
+  dom::BrowserBridgeParent* bridge = embeddedBrowser->GetBrowserBridgeParent();
+  if (bridge) {
+    // aChildDoc is an embedded document in a different content process to
+    // this document.
+    // Send a COM proxy for the embedded document to the embedder process
+    // hosting the iframe. This will be returned as the child of the
+    // embedder OuterDocAccessible.
+    RefPtr<IDispatch> docAcc;
+    aChildDoc->GetCOMInterface((void**)getter_AddRefs(docAcc));
+    RefPtr<IDispatch> docWrapped(
+        mscom::PassthruProxy::Wrap<IDispatch>(WrapNotNull(docAcc)));
+    IDispatchHolder::COMPtrType docPtr(
+        mscom::ToProxyUniquePtr(std::move(docWrapped)));
+    IDispatchHolder docHolder(std::move(docPtr));
+    if (bridge->SendSetEmbeddedDocAccessibleCOMProxy(docHolder)) {
+#  if defined(MOZ_SANDBOX)
+      mDocProxyStream = docHolder.GetPreservedStream();
+#  endif  // defined(MOZ_SANDBOX)
+    }
+  }
+#endif  // defined(XP_WIN)
+
   return IPC_OK();
 }
 

accessible/ipc/DocAccessibleParent.h

@@ -268,6 +268,7 @@ class DocAccessibleParent : public ProxyAccessible,
 
 #  if defined(MOZ_SANDBOX)
   mscom::PreservedStreamPtr mParentProxyStream;
+  mscom::PreservedStreamPtr mDocProxyStream;
 #  endif  // defined(MOZ_SANDBOX)
 #endif    // defined(XP_WIN)
 

dom/ipc/BrowserParent.cpp

@@ -1126,6 +1126,11 @@ mozilla::ipc::IPCResult BrowserParent::RecvPDocAccessibleConstructor(
     // In this case, we don't get aParentDoc and aParentID.
     MOZ_ASSERT(!aParentDoc && !aParentID);
     MOZ_ASSERT(embedderID);
+#  ifdef XP_WIN
+    MOZ_ASSERT(!aDocCOMProxy.IsNull());
+    RefPtr<IAccessible> proxy(aDocCOMProxy.Get());
+    doc->SetCOMInterface(proxy);
+#  endif
     mozilla::ipc::IPCResult added = embedderDoc->AddChildDoc(doc, embedderID);
     if (!added) {
 #  ifdef DEBUG