Bug 1234583 -Expose OS Pid in nsITabParent. r=billm

dom/interfaces/base/nsITabParent.idl

@@ -54,6 +54,11 @@ interface nsITabParent : nsISupports
 
   readonly attribute uint64_t tabId;
 
+  /**
+   * The OS level process Id of the related child process.
+   */
+  readonly attribute int32_t osPid;
+
   /**
    * Navigate by key. If aForDocumentNavigation is true, navigate by document.
    * If aForDocumentNavigation is false, navigate by element.

dom/ipc/ContentBridgeParent.h

@@ -62,6 +62,11 @@ public:
   {
     return mIsForBrowser;
   }
+  virtual int32_t Pid() const override
+  {
+    // XXX: do we need this for ContentBridgeParent?
+    return -1;
+  }
 
 protected:
   virtual ~ContentBridgeParent();

dom/ipc/ContentParent.h

@@ -386,8 +386,6 @@ public:
     return mSubprocess;
   }
 
-  int32_t Pid() const;
-
   ContentParent* Opener() const
   {
     return mOpener;
@@ -591,6 +589,8 @@ public:
   virtual bool
   RecvUnstoreAndBroadcastBlobURLUnregistration(const nsCString& aURI) override;
 
+  virtual int32_t Pid() const override;
+
 protected:
   void OnChannelConnected(int32_t pid) override;
 

dom/ipc/TabParent.cpp

@@ -2943,6 +2943,13 @@ TabParent::GetTabId(uint64_t* aId)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+TabParent::GetOsPid(int32_t* aId)
+{
+  *aId = Manager()->Pid();
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 TabParent::GetHasContentOpener(bool* aResult)
 {

dom/ipc/nsIContentParent.h

@@ -82,6 +82,8 @@ public:
 
   ContentBridgeParent* AsContentBridgeParent();
 
+  virtual int32_t Pid() const = 0;
+
 protected: // methods
   bool CanOpenBrowser(const IPCTabContext& aContext);