Avoids the "re-encode HPACK as SPDY3" step.

net/spdy/mock_spdy_framer_visitor.h

Index: net/spdy/mock_spdy_framer_visitor.h
diff --git a/net/spdy/mock_spdy_framer_visitor.h b/net/spdy/mock_spdy_framer_visitor.h
index ac97a3dbb814183f48bb2ab13eacd75d04fcd720..dcf7356abc0032bb757751eb62bc2c6961129e53 100644
--- a/net/spdy/mock_spdy_framer_visitor.h
+++ b/net/spdy/mock_spdy_framer_visitor.h
@@ -10,6 +10,7 @@
 
 #include "base/strings/string_piece.h"
 #include "net/spdy/spdy_framer.h"
+#include "net/spdy/spdy_test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace net {
@@ -75,6 +76,31 @@ class MockSpdyFramerVisitor : public SpdyFramerVisitorInterface {
                     uint8_t weight,
                     bool exclusive));
   MOCK_METHOD2(OnUnknownFrame, bool(SpdyStreamId stream_id, int frame_type));
+
+  void DelegateNewHeaderHandling() {
+    ON_CALL(*this, OnHeaderFrameStart(testing::_))
+        .WillByDefault(testing::Invoke(
+            this, &MockSpdyFramerVisitor::ReturnTestHeadersHandler));
+    ON_CALL(*this, OnHeaderFrameEnd(testing::_, testing::_))
+        .WillByDefault(testing::Invoke(
+            this, &MockSpdyFramerVisitor::ResetTestHeadersHandler));
+  }
+
+  SpdyHeadersHandlerInterface* ReturnTestHeadersHandler(
+      SpdyStreamId /* stream_id */) {
+    if (headers_handler_ == nullptr) {
+      headers_handler_.reset(new TestHeadersHandler);
+    }
+    return headers_handler_.get();
+  }
+
+  void ResetTestHeadersHandler(SpdyStreamId /* stream_id */, bool end) {
+    if (end) {
+      headers_handler_.reset();
+    }
+  }
+
+  std::unique_ptr<SpdyHeadersHandlerInterface> headers_handler_;
 };
 
 }  // namespace test