Add layout tests to check Accept request header values observed by Service Worker

third_party/WebKit/LayoutTests/http/tests/serviceworker/fetch-event.html

Index: third_party/WebKit/LayoutTests/http/tests/serviceworker/fetch-event.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/serviceworker/fetch-event.html b/third_party/WebKit/LayoutTests/http/tests/serviceworker/fetch-event.html
index a27c2b9490fdff21e50bdaec2743070d49166626..5727db91180bb345d90b46df8278e29fe7e7afcd 100644
--- a/third_party/WebKit/LayoutTests/http/tests/serviceworker/fetch-event.html
+++ b/third_party/WebKit/LayoutTests/http/tests/serviceworker/fetch-event.html
@@ -110,6 +110,25 @@ async_test(function(t) {
   }, 'Service Worker responds to fetch event with a client id');
 
 async_test(function(t) {
+    var scope = 'resources/simple.html?accept';
+    service_worker_unregister_and_register(t, worker, scope)
+      .then(function(reg) {
+          return wait_for_state(t, reg.installing, 'activated');
+        })
+      .then(function() { return with_iframe(scope); })
+      .then(function(frame) {
+          assert_equals(
+            frame.contentDocument.body.textContent,
+            // Spec: 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
+            'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
+            'Accept header value for navigation request should be visible to Service Worker');
+          frame.remove();

[nhiroki, 2016/04/11 08:33:29]

Thanks to (*), an iframe created by with_iframe() is now automatically removed
at the end of tests and you don't have to explicitly call frame.remove()
anymore.

(*) https://codereview.chromium.org/1859343002/

+          return service_worker_unregister_and_done(t, scope);
+        })
+      .catch(unreached_rejection(t));
+  }, 'Accept header value for navigation request visible to Service Worker');
+
+async_test(function(t) {
     var scope = 'resources/simple.html?ignore';
     service_worker_unregister_and_register(t, worker, scope)
       .then(function(reg) {