Add comment to BodyStreamBuffer accessors for Response class

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

Index: third_party/WebKit/Source/modules/fetch/FetchResponseData.h
diff --git a/third_party/WebKit/Source/modules/fetch/FetchResponseData.h b/third_party/WebKit/Source/modules/fetch/FetchResponseData.h
index b4aab0268d9119362781d97c803220e01cc7da06..4b0c0635acd27198986248c157f0c96b34d8558c 100644
--- a/third_party/WebKit/Source/modules/fetch/FetchResponseData.h
+++ b/third_party/WebKit/Source/modules/fetch/FetchResponseData.h
@@ -59,6 +59,8 @@ public:
     FetchHeaderList* headerList() const { return m_headerList.get(); }
     BodyStreamBuffer* buffer() const { return m_buffer; }
     String mimeType() const;
+    // Returns the BodyStreamBuffer of |m_internalResponse| if any. Otherwise,
+    // returns |m_buffer|.
     BodyStreamBuffer* internalBuffer() const;
     String internalMIMEType() const;
     int64_t responseTime() const { return m_responseTime; }