[Fetch API] Reflect spec changes of bodyUsed property

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

Index: third_party/WebKit/Source/modules/fetch/Response.cpp
diff --git a/third_party/WebKit/Source/modules/fetch/Response.cpp b/third_party/WebKit/Source/modules/fetch/Response.cpp
index a7d2421779c49e3e92b48b318430457c06533cd1..7ca6de459e0389fae07f31b3ad6a1c8f7836fc7d 100644
--- a/third_party/WebKit/Source/modules/fetch/Response.cpp
+++ b/third_party/WebKit/Source/modules/fetch/Response.cpp
@@ -339,7 +339,7 @@ Headers* Response::headers() const
 
 Response* Response::clone(ExceptionState& exceptionState)
 {
-    if (bodyUsed()) {
+    if (isBodyLocked() || bodyUsed()) {
         exceptionState.throwTypeError("Response body is already used");
         return nullptr;
     }
@@ -390,6 +390,11 @@ bool Response::hasBody() const
     return m_response->internalBuffer();
 }
 
+bool Response::bodyUsed()
+{
+    return internalBodyBuffer() && internalBodyBuffer()->stream()->isDisturbed();
+}
+
 String Response::mimeType() const
 {
     return m_response->mimeType();