Bug 1550560 - Part 3: Make BrowserBridgeParent refcounted in IPDL, r=mccr8

This is an example refcounted actor which was easy enough to port over as an
initial test. More can be ported in the future, potentially alongside removing
`mIPCOpen`.

Differential Revision: https://phabricator.services.mozilla.com/D39503

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

dom/ipc/BrowserBridgeChild.h

@@ -29,7 +29,7 @@ class BrowserBridgeChild : public PBrowserBridgeChild {
  public:
   typedef mozilla::layers::LayersId LayersId;
 
-  NS_INLINE_DECL_REFCOUNTING(BrowserBridgeChild);
+  NS_INLINE_DECL_REFCOUNTING(BrowserBridgeChild, final);
 
   BrowserChild* Manager() {
     MOZ_ASSERT(mIPCOpen);

dom/ipc/BrowserBridgeParent.h

@@ -27,7 +27,7 @@ class BrowserParent;
  */
 class BrowserBridgeParent : public PBrowserBridgeParent {
  public:
-  NS_INLINE_DECL_REFCOUNTING(BrowserBridgeParent);
+  NS_INLINE_DECL_REFCOUNTING(BrowserBridgeParent, final);
 
   BrowserBridgeParent();
 

dom/ipc/BrowserChild.cpp

@@ -3287,22 +3287,14 @@ bool BrowserChild::DeallocPWindowGlobalChild(PWindowGlobalChild* aActor) {
   return true;
 }
 
-PBrowserBridgeChild* BrowserChild::AllocPBrowserBridgeChild(const nsString&,
-                                                            const nsString&,
-                                                            BrowsingContext*,
-                                                            const uint32_t&,
-                                                            const TabId&) {
+already_AddRefed<PBrowserBridgeChild> BrowserChild::AllocPBrowserBridgeChild(
+    const nsString&, const nsString&, BrowsingContext*, const uint32_t&,
+    const TabId&) {
   MOZ_CRASH(
       "We should never be manually allocating PBrowserBridgeChild actors");
   return nullptr;
 }
 
-bool BrowserChild::DeallocPBrowserBridgeChild(PBrowserBridgeChild* aActor) {
-  // This reference was added in BrowserBridgeChild::Create.
-  static_cast<BrowserBridgeChild*>(aActor)->Release();
-  return true;
-}
-
 ScreenIntSize BrowserChild::GetInnerSize() {
   LayoutDeviceIntSize innerSize =
       RoundedToInt(mUnscaledInnerSize * mPuppetWidget->GetDefaultScale());

dom/ipc/BrowserChild.h

@@ -663,13 +663,11 @@ class BrowserChild final : public nsMessageManagerScriptExecutor,
 
   bool DeallocPWindowGlobalChild(PWindowGlobalChild* aActor);
 
-  PBrowserBridgeChild* AllocPBrowserBridgeChild(
+  already_AddRefed<PBrowserBridgeChild> AllocPBrowserBridgeChild(
       const nsString& aName, const nsString& aRemoteType,
       BrowsingContext* aBrowsingContext, const uint32_t& aChromeFlags,
       const TabId& aTabId);
 
-  bool DeallocPBrowserBridgeChild(PBrowserBridgeChild* aActor);
-
   mozilla::ipc::IPCResult RecvDestroy();
 
   mozilla::ipc::IPCResult RecvSetDocShellIsActive(const bool& aIsActive);

dom/ipc/BrowserParent.cpp

@@ -1266,18 +1266,11 @@ IPCResult BrowserParent::RecvPBrowserBridgeConstructor(
   return IPC_OK();
 }
 
-PBrowserBridgeParent* BrowserParent::AllocPBrowserBridgeParent(
+already_AddRefed<PBrowserBridgeParent> BrowserParent::AllocPBrowserBridgeParent(
     const nsString& aName, const nsString& aRemoteType,
     BrowsingContext* aBrowsingContext, const uint32_t& aChromeFlags,
     const TabId& aTabId) {
-  // Reference freed in DeallocPBrowserBridgeParent.
-  return do_AddRef(new BrowserBridgeParent()).take();
-}
-
-bool BrowserParent::DeallocPBrowserBridgeParent(PBrowserBridgeParent* aActor) {
-  // Free reference from AllocPBrowserBridgeParent.
-  static_cast<BrowserBridgeParent*>(aActor)->Release();
-  return true;
+  return do_AddRef(new BrowserBridgeParent());
 }
 
 void BrowserParent::SendMouseEvent(const nsAString& aType, float aX, float aY,

dom/ipc/BrowserParent.h

@@ -477,13 +477,11 @@ class BrowserParent final : public PBrowserParent,
   virtual mozilla::ipc::IPCResult RecvPWindowGlobalConstructor(
       PWindowGlobalParent* aActor, const WindowGlobalInit& aInit) override;
 
-  PBrowserBridgeParent* AllocPBrowserBridgeParent(
+  already_AddRefed<PBrowserBridgeParent> AllocPBrowserBridgeParent(
       const nsString& aPresentationURL, const nsString& aRemoteType,
       BrowsingContext* aBrowsingContext, const uint32_t& aChromeFlags,
       const TabId& aTabId);
 
-  bool DeallocPBrowserBridgeParent(PBrowserBridgeParent* aActor);
-
   virtual mozilla::ipc::IPCResult RecvPBrowserBridgeConstructor(
       PBrowserBridgeParent* aActor, const nsString& aPresentationURL,
       const nsString& aRemoteType, BrowsingContext* aBrowsingContext,

dom/ipc/ContentChild.cpp

@@ -2072,10 +2072,8 @@ already_AddRefed<RemoteBrowser> ContentChild::CreateBrowser(
   TabId tabId(nsContentUtils::GenerateTabId());
   RefPtr<BrowserBridgeChild> browserBridge =
       new BrowserBridgeChild(aFrameLoader, aBrowsingContext, tabId);
-  // Reference is freed in BrowserChild::DeallocPBrowserBridgeChild.
   browserChild->SendPBrowserBridgeConstructor(
-      do_AddRef(browserBridge).take(),
-      PromiseFlatString(aContext.PresentationURL()), aRemoteType,
+      browserBridge, PromiseFlatString(aContext.PresentationURL()), aRemoteType,
       aBrowsingContext, chromeFlags, tabId);
   browserBridge->mIPCOpen = true;
 

dom/ipc/PBrowserBridge.ipdl

@@ -30,7 +30,7 @@ namespace dom {
  * See `dom/docs/Fission-IPC-Diagram.svg` for an overview of the DOM IPC
  * actors.
  */
-async protocol PBrowserBridge {
+async refcounted protocol PBrowserBridge {
   manager PBrowser;
 
 child: