save-data header value gets appended on page refreshes

third_party/WebKit/Source/core/loader/FrameFetchContextTest.cpp

 /*
  * Copyright (c) 2015, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 546 matching lines @@
     EXPECT_EQ(ResourceLoadPriorityVeryLow, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityMedium, Resource::Script, request, ResourcePriority::NotVisible));
 }
 
 TEST_F(FrameFetchContextTest, EnableDataSaver)
 {
     Settings* settings = document->frame()->settings();
     settings->setDataSaverEnabled(true);
     ResourceRequest resourceRequest("http://www.example.com");
     fetchContext->addAdditionalRequestHeaders(resourceRequest, FetchMainResource);
     EXPECT_STREQ("on", resourceRequest.httpHeaderField("Save-Data").utf8().data());
+
+    // Subsequent call to addAdditionalRequestHeaders should not append to the
+    // save-data header.
+    fetchContext->addAdditionalRequestHeaders(resourceRequest, FetchMainResource);
+    EXPECT_STREQ("on", resourceRequest.httpHeaderField("Save-Data").utf8().data());
 }
 
 TEST_F(FrameFetchContextTest, DisabledDataSaver)
 {
     ResourceRequest resourceRequest("http://www.example.com");
     fetchContext->addAdditionalRequestHeaders(resourceRequest, FetchMainResource);
     EXPECT_STREQ("", resourceRequest.httpHeaderField("Save-Data").utf8().data());
 }
 
 // Tests that when a resource with certificate errors is loaded from the
@@ skipping 146 matching lines @@
         fetchContext->addAdditionalRequestHeaders(mainRequest, FetchMainResource);
         EXPECT_EQ(mainRequest.isExternalRequest(), test.isExternalExpectation);
 
         ResourceRequest subRequest(test.url);
         fetchContext->addAdditionalRequestHeaders(subRequest, FetchSubresource);
         EXPECT_EQ(subRequest.isExternalRequest(), test.isExternalExpectation);
     }
 }
 
 } // namespace blink