Bug 1585306 - nsILoadGroup observes last-pb-context-exit to monitor the browsing context, r=mayhemer

Differential Revision: https://phabricator.services.mozilla.com/D66745

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

netwerk/base/nsILoadGroup.idl

@@ -95,4 +95,11 @@ interface nsILoadGroup : nsIRequest
      * the docShell has created the default request.)
      */
     attribute nsLoadFlags defaultLoadFlags;
+
+    /**
+     * Returns true if the loadGroup belongs to a discarded context, such as, a
+     * terminated private browsing session.
+     */
+    [infallible]
+    readonly attribute boolean isBrowsingContextDiscarded;
 };

netwerk/base/nsLoadGroup.cpp

@@ -11,6 +11,7 @@
 #include "nsArrayEnumerator.h"
 #include "nsCOMArray.h"
 #include "nsCOMPtr.h"
+#include "nsContentUtils.h"
 #include "mozilla/Logging.h"
 #include "nsString.h"
 #include "nsTArray.h"
@@ -91,6 +92,7 @@ nsLoadGroup::nsLoadGroup()
       mStatus(NS_OK),
       mIsCanceling(false),
       mDefaultLoadIsTimed(false),
+      mBrowsingContextDiscarded(false),
       mTimedRequests(0),
       mCachedRequests(0) {
   LOG(("LOADGROUP [%p]: Created.\n", this));
@@ -106,6 +108,11 @@ nsLoadGroup::~nsLoadGroup() {
     mRequestContextService->RemoveRequestContext(mRequestContext->GetID());
   }
 
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    Unused << os->RemoveObserver(this, "last-pb-context-exited");
+  }
+
   LOG(("LOADGROUP [%p]: Destroyed.\n", this));
 }
 
@@ -113,7 +120,7 @@ nsLoadGroup::~nsLoadGroup() {
 // nsISupports methods:
 
 NS_IMPL_ISUPPORTS(nsLoadGroup, nsILoadGroup, nsILoadGroupChild, nsIRequest,
-                  nsISupportsPriority, nsISupportsWeakReference)
+                  nsISupportsPriority, nsISupportsWeakReference, nsIObserver)
 
 ////////////////////////////////////////////////////////////////////////////////
 // nsIRequest methods:
@@ -960,6 +967,31 @@ nsresult nsLoadGroup::Init() {
         getter_AddRefs(mRequestContext));
   }
 
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  NS_ENSURE_STATE(os);
+
+  Unused << os->AddObserver(this, "last-pb-context-exited", true);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsLoadGroup::Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) {
+  MOZ_ASSERT(!strcmp(aTopic, "last-pb-context-exited"));
+
+  OriginAttributes attrs = nsContentUtils::GetOriginAttributes(this);
+  if (attrs.mPrivateBrowsingId == 0) {
+    return NS_OK;
+  }
+
+  mBrowsingContextDiscarded = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsLoadGroup::GetIsBrowsingContextDiscarded(bool* aIsBrowsingContextDiscarded) {
+  *aIsBrowsingContextDiscarded = mBrowsingContextDiscarded;
   return NS_OK;
 }
 

netwerk/base/nsLoadGroup.h

@@ -8,6 +8,7 @@
 
 #include "nsILoadGroup.h"
 #include "nsILoadGroupChild.h"
+#include "nsIObserver.h"
 #include "nsCOMPtr.h"
 #include "nsWeakReference.h"
 #include "nsISupportsPriority.h"
@@ -23,6 +24,7 @@ namespace net {
 
 class nsLoadGroup : public nsILoadGroup,
                     public nsILoadGroupChild,
+                    public nsIObserver,
                     public nsISupportsPriority,
                     public nsSupportsWeakReference {
  public:
@@ -44,6 +46,10 @@ class nsLoadGroup : public nsILoadGroup,
   // nsISupportsPriority methods:
   NS_DECL_NSISUPPORTSPRIORITY
 
+  ////////////////////////////////////////////////////////////////////////////
+  // nsIObserver methods:
+  NS_DECL_NSIOBSERVER
+
   ////////////////////////////////////////////////////////////////////////////
   // nsLoadGroup methods:
 
@@ -85,6 +91,7 @@ class nsLoadGroup : public nsILoadGroup,
   nsresult mStatus;
   bool mIsCanceling;
   bool mDefaultLoadIsTimed;
+  bool mBrowsingContextDiscarded;
 
   /* Telemetry */
   mozilla::TimeStamp mDefaultRequestCreationTime;

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -2132,6 +2132,14 @@ void HttpBaseChannel::NotifySetCookie(const nsACString& aCookie) {
   }
 }
 
+bool HttpBaseChannel::IsBrowsingContextDiscarded() const {
+  if (mLoadGroup && mLoadGroup->GetIsBrowsingContextDiscarded()) {
+    return true;
+  }
+
+  return false;
+}
+
 NS_IMETHODIMP
 HttpBaseChannel::SetCookie(const nsACString& aCookieHeader) {
   if (mLoadFlags & LOAD_ANONYMOUS) return NS_OK;

netwerk/protocol/http/HttpBaseChannel.h

@@ -601,6 +601,8 @@ class HttpBaseChannel : public nsHashPropertyBag,
 
   void MaybeFlushConsoleReports();
 
+  bool IsBrowsingContextDiscarded() const;
+
   friend class PrivateBrowsingChannel<HttpBaseChannel>;
   friend class InterceptFailedOnStop;