Implment BytesConsumer::tee

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

Index: third_party/WebKit/Source/modules/fetch/BytesConsumer.h
diff --git a/third_party/WebKit/Source/modules/fetch/BytesConsumer.h b/third_party/WebKit/Source/modules/fetch/BytesConsumer.h
index 894cfb71a87de559dfdebbea6fe029f5757c64e2..a4a8525d1d33fa8e544df1f3fd81ceeb8fd3eeb9 100644
--- a/third_party/WebKit/Source/modules/fetch/BytesConsumer.h
+++ b/third_party/WebKit/Source/modules/fetch/BytesConsumer.h
@@ -14,6 +14,8 @@
 
 namespace blink {
 
+class ExecutionContext;
+
 // BytesConsumer represents the "consumer" side of a data pipe. A user
 // can read data from it.
 //
@@ -139,6 +141,11 @@ public:
     // implementation for debug purpose.
     virtual String debugName() const = 0;
 
+    // Creates two BytesConsumer both of which represent the data sequence that
+    // would be read from |src| and store them to |*dest1| and |*dest2|.
+    // |src| must not have a client when called.
+    static void tee(ExecutionContext*, BytesConsumer* src, BytesConsumer** dest1, BytesConsumer** dest2);
+
     DEFINE_INLINE_VIRTUAL_TRACE() {}
 
 protected: