Revert of Introduce ExclusiveStreamReader.

Source/modules/fetch/Body.cpp

Index: Source/modules/fetch/Body.cpp
diff --git a/Source/modules/fetch/Body.cpp b/Source/modules/fetch/Body.cpp
index b90a6ca9c0452344f034f2e65f0a02c6656e8c4c..3d2b1cdfb4a0722f35a48d56d4693ca4a4035e87 100644
--- a/Source/modules/fetch/Body.cpp
+++ b/Source/modules/fetch/Body.cpp
@@ -113,8 +113,8 @@
         }
         // Take back the data in |m_stream|.
         Deque<std::pair<RefPtr<DOMArrayBuffer>, size_t>> tmp_queue;
-        if (m_stream->stateInternal() == ReadableStream::Readable)
-            m_stream->readInternal(tmp_queue);
+        if (m_stream->state() == ReadableStream::Readable)
+            m_stream->read(tmp_queue);
         *dataLost = m_queueCount != tmp_queue.size();
         while (!tmp_queue.isEmpty()) {
             std::pair<RefPtr<DOMArrayBuffer>, size_t> data = tmp_queue.takeFirst();
@@ -379,7 +379,7 @@
 {
     if (m_resolver)
         return true;
-    if (m_stream && m_stream->hasPendingActivity())
+    if (m_stream && (m_stream->state() == ReadableStream::Readable || m_stream->state() == ReadableStream::Waiting))
         return true;
     return false;
 }