From 1112382b61c21ee0512bf23edc54aeed5b9f059c Mon Sep 17 00:00:00 2001
From: Phil Ringnalda <philringnalda@gmail.com>
Date: Thu, 21 Sep 2017 20:29:39 -0700
Subject: [PATCH] Backed out 2 changesets (bug 1401461) for being the wrong
 patches

Backed out changeset 20a0000f97bc (bug 1401461)
Backed out changeset e3c36a62b5b1 (bug 1401461)

MozReview-Commit-ID: BJeIuoGJwjb
---
 dom/media/ChannelMediaResource.cpp | 33 ++++++------------------------
 dom/media/ChannelMediaResource.h   |  9 ++------
 2 files changed, 8 insertions(+), 34 deletions(-)

diff --git a/dom/media/ChannelMediaResource.cpp b/dom/media/ChannelMediaResource.cpp
index ba4fd51636fb..dbb27b0bb375 100644
--- a/dom/media/ChannelMediaResource.cpp
+++ b/dom/media/ChannelMediaResource.cpp
@@ -68,7 +68,6 @@ nsresult
 ChannelMediaResource::Listener::OnStartRequest(nsIRequest* aRequest,
                                                nsISupports* aContext)
 {
-  MOZ_ASSERT(NS_IsMainThread());
   if (!mResource)
     return NS_OK;
   return mResource->OnStartRequest(aRequest, mOffset);
@@ -79,7 +78,6 @@ ChannelMediaResource::Listener::OnStopRequest(nsIRequest* aRequest,
                                               nsISupports* aContext,
                                               nsresult aStatus)
 {
-  MOZ_ASSERT(NS_IsMainThread());
   if (!mResource)
     return NS_OK;
   return mResource->OnStopRequest(aRequest, aStatus);
@@ -93,14 +91,8 @@ ChannelMediaResource::Listener::OnDataAvailable(nsIRequest* aRequest,
                                                 uint32_t aCount)
 {
   // This might happen off the main thread.
-  RefPtr<ChannelMediaResource> res;
-  {
-    MutexAutoLock lock(mMutex);
-    res = mResource;
-  }
-  // Note Rekove() might happen at the same time to reset mResource. We check
-  // the load ID to determine if the data is from an old channel.
-  return res ? res->OnDataAvailable(mLoadID, aStream, aCount) : NS_OK;
+  MOZ_DIAGNOSTIC_ASSERT(mResource);
+  return mResource->OnDataAvailable(mLoadID, aStream, aCount);
 }
 
 nsresult
@@ -110,8 +102,6 @@ ChannelMediaResource::Listener::AsyncOnChannelRedirect(
   uint32_t aFlags,
   nsIAsyncVerifyRedirectCallback* cb)
 {
-  MOZ_ASSERT(NS_IsMainThread());
-
   nsresult rv = NS_OK;
   if (mResource) {
     rv = mResource->OnChannelRedirect(aOld, aNew, aFlags, mOffset);
@@ -137,14 +127,6 @@ ChannelMediaResource::Listener::GetInterface(const nsIID& aIID, void** aResult)
   return QueryInterface(aIID, aResult);
 }
 
-void
-ChannelMediaResource::Listener::Revoke()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  MutexAutoLock lock(mMutex);
-  mResource = nullptr;
-}
-
 static bool
 IsPayloadCompressed(nsIHttpChannel* aChannel)
 {
@@ -433,16 +415,13 @@ ChannelMediaResource::OnDataAvailable(uint32_t aLoadID,
                                       uint32_t aCount)
 {
   // This might happen off the main thread.
+  // Don't assert |mChannel.get() == aRequest| since reading mChannel here off
+  // the main thread is a data race.
 
   RefPtr<ChannelMediaResource> self = this;
   nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
-    "ChannelMediaResource::OnDataAvailable", [self, aCount, aLoadID]() {
-      if (aLoadID != self->mLoadID) {
-        // Ignore data from the old channel.
-        return;
-      }
-      self->mChannelStatistics.AddBytes(aCount);
-    });
+    "ChannelMediaResource::OnDataAvailable",
+    [self, aCount]() { self->mChannelStatistics.AddBytes(aCount); });
   mCallback->AbstractMainThread()->Dispatch(r.forget());
 
   Closure closure{ aLoadID, this };
diff --git a/dom/media/ChannelMediaResource.h b/dom/media/ChannelMediaResource.h
index f8ee12248d16..f7221de8007c 100644
--- a/dom/media/ChannelMediaResource.h
+++ b/dom/media/ChannelMediaResource.h
@@ -116,8 +116,7 @@ public:
     ~Listener() {}
   public:
     Listener(ChannelMediaResource* aResource, int64_t aOffset, uint32_t aLoadID)
-      : mMutex("Listener.mMutex")
-      , mResource(aResource)
+      : mResource(aResource)
       , mOffset(aOffset)
       , mLoadID(aLoadID)
     {}
@@ -129,13 +128,9 @@ public:
     NS_DECL_NSIINTERFACEREQUESTOR
     NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
 
-    void Revoke();
+    void Revoke() { mResource = nullptr; }
 
   private:
-    Mutex mMutex;
-    // mResource should only be modified on the main thread with the lock.
-    // So it can be read without lock on the main thread or on other threads
-    // with the lock.
     RefPtr<ChannelMediaResource> mResource;
     const int64_t mOffset;
     const uint32_t mLoadID;