Actually handle the Vary header in blink, rather than punting on sight.

third_party/WebKit/Source/platform/loader/fetch/ResourceTest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/loader/fetch/Resource.h"
 
 #include "platform/SharedBuffer.h"
 #include "platform/loader/fetch/RawResource.h"
 #include "platform/network/ResourceRequest.h"
 #include "platform/network/ResourceResponse.h"
@@ skipping 72 matching lines @@
   // Revalidating with a url that differs by only the fragment
   // shouldn't trigger a securiy check.
   url.setFragmentIdentifier("bar");
   resource->setRevalidatingRequest(ResourceRequest(url));
   ResourceResponse revalidatingResponse;
   revalidatingResponse.setURL(url);
   revalidatingResponse.setHTTPStatusCode(304);
   resource->responseReceived(revalidatingResponse, nullptr);
 }
 
+TEST(ResourceTest, Vary) {
+  ScopedTestingPlatformSupport<MockPlatform> mock;
+  KURL url(ParsedURLString, "http://127.0.0.1:8000/foo.html");
+  ResourceResponse response;
+  response.setURL(url);
+  response.setHTTPStatusCode(200);
+
+  Resource* resource = RawResource::create(url, Resource::Raw);
+  resource->responseReceived(response, nullptr);
+  resource->finish();
+
+  ResourceRequest newRequest(url);
+  EXPECT_FALSE(resource->mustReloadDueToVaryHeader(newRequest));
+
+  response.setHTTPHeaderField(HTTPNames::Vary, "*");
+  resource->setResponse(response);
+  EXPECT_TRUE(resource->mustReloadDueToVaryHeader(newRequest));
+
+  // Irrelevant header
+  response.setHTTPHeaderField(HTTPNames::Vary, "definitelynotarealheader");
+  resource->setResponse(response);
+  EXPECT_FALSE(resource->mustReloadDueToVaryHeader(newRequest));
+
+  // Header present on new but not old
+  newRequest.setHTTPHeaderField(HTTPNames::User_Agent, "something");
+  response.setHTTPHeaderField(HTTPNames::Vary, HTTPNames::User_Agent);
+  resource->setResponse(response);
+  EXPECT_TRUE(resource->mustReloadDueToVaryHeader(newRequest));
+  newRequest.clearHTTPHeaderField(HTTPNames::User_Agent);
+
+  ResourceRequest oldRequest(url);
+  oldRequest.setHTTPHeaderField(HTTPNames::User_Agent, "something");
+  oldRequest.setHTTPHeaderField(HTTPNames::Referer, "http://foo.com");
+  resource = RawResource::create(oldRequest, Resource::Raw);
+  resource->responseReceived(response, nullptr);
+  resource->finish();
+
+  // Header present on old but not new
+  newRequest.clearHTTPHeaderField(HTTPNames::User_Agent);
+  response.setHTTPHeaderField(HTTPNames::Vary, HTTPNames::User_Agent);
+  resource->setResponse(response);
+  EXPECT_TRUE(resource->mustReloadDueToVaryHeader(newRequest));
+
+  // Header present on both
+  newRequest.setHTTPHeaderField(HTTPNames::User_Agent, "something");
+  EXPECT_FALSE(resource->mustReloadDueToVaryHeader(newRequest));
+
+  // One matching, one mismatching
+  response.setHTTPHeaderField(HTTPNames::Vary, "User-Agent, Referer");
+  resource->setResponse(response);
+  EXPECT_TRUE(resource->mustReloadDueToVaryHeader(newRequest));
+
+  // Two matching
+  newRequest.setHTTPHeaderField(HTTPNames::Referer, "http://foo.com");
+  EXPECT_FALSE(resource->mustReloadDueToVaryHeader(newRequest));
+}
+
 }  // namespace blink