BytesConsumer::endRead can return Done

third_party/WebKit/Source/modules/fetch/BytesConsumer.cpp

Index: third_party/WebKit/Source/modules/fetch/BytesConsumer.cpp
diff --git a/third_party/WebKit/Source/modules/fetch/BytesConsumer.cpp b/third_party/WebKit/Source/modules/fetch/BytesConsumer.cpp
index f1584d0c76b0207a86630cf5082dd757e4ad425e..a71ad8a94f36ecdca2d8130f9508cc31d2e54086 100644
--- a/third_party/WebKit/Source/modules/fetch/BytesConsumer.cpp
+++ b/third_party/WebKit/Source/modules/fetch/BytesConsumer.cpp
@@ -48,23 +48,28 @@ public:
         while (true) {
             const char* buffer = nullptr;
             size_t available = 0;
-            switch (m_src->beginRead(&buffer, &available)) {
-            case Result::Ok: {
-                Chunk* chunk = new Chunk(buffer, available);
-                if (m_src->endRead(available) != Result::Ok) {
-                    clearAndNotify();
-                    return;
-                }
+            auto result = m_src->beginRead(&buffer, &available);
+            if (result == Result::ShouldWait) {
+                if (hasEnqueued && destination1WasEmpty)
+                    m_destination1->notify();
+                if (hasEnqueued && destination2WasEmpty)
+                    m_destination2->notify();
+                return;
+            }
+            Chunk* chunk = nullptr;
+            if (result == Result::Ok) {
+                chunk = new Chunk(buffer, available);
+                result = m_src->endRead(available);
+            }
+            switch (result) {
+            case Result::Ok:
+                DCHECK(chunk);
                 m_destination1->enqueue(chunk);
                 m_destination2->enqueue(chunk);
                 hasEnqueued = true;
                 break;
-            }
             case Result::ShouldWait:
-                if (hasEnqueued && destination1WasEmpty)
-                    m_destination1->notify();
-                if (hasEnqueued && destination2WasEmpty)
-                    m_destination2->notify();
+                NOTREACHED();
                 return;
             case Result::Done:
                 if (destination1WasEmpty)