BodyStreamBuffer should release WebDataConsumerHandle::Reader eagerly

third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.h

Index: third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.h
diff --git a/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.h b/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.h
index e0eb8f5901a9333b94776069bf7dca7ffc482330..5ea82d05b5f7097aaab44bf91719f8012b5c269a 100644
--- a/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.h
+++ b/third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.h
@@ -25,6 +25,7 @@ class ExecutionContext;
 class MODULES_EXPORT BodyStreamBuffer final : public GarbageCollectedFinalized<BodyStreamBuffer>, public UnderlyingSource, public WebDataConsumerHandle::Client {
     WTF_MAKE_NONCOPYABLE(BodyStreamBuffer);
     USING_GARBAGE_COLLECTED_MIXIN(BodyStreamBuffer);
+    USING_PRE_FINALIZER(BodyStreamBuffer, stop);

[sof, 2016/02/19 06:17:11]

This prefinalizer (and its registration) is correct, but the action itself isn't
very interesting (wrt access of other Oilpan objects when finalizing), hence
adding a smaller, but avoidable, overhead during GC.

I'd argue that EAGERLY_FINALIZE() is what you want here instead.

[yhirano, 2016/02/19 06:36:22]

Sorry I don't understand EAGERLY_FINALIZE: Can you tell me what it is? What is
the difference between them?

 public:
     // |handle| cannot be null and cannot be locked.
     explicit BodyStreamBuffer(PassOwnPtr<FetchDataConsumerHandle> /* handle */);
@@ -70,7 +71,7 @@ private:
 
     OwnPtr<FetchDataConsumerHandle> m_handle;
     OwnPtr<FetchDataConsumerHandle::Reader> m_reader;
-    Member<ReadableByteStream> m_stream;
+    const Member<ReadableByteStream> m_stream;

[sof, 2016/02/19 06:17:11]

( what's the concern? )

[yhirano, 2016/02/19 17:32:22]

Done.

     // We need this member to keep it alive while loading.
     Member<FetchDataLoader> m_loader;
     bool m_streamNeedsMore;