Implement THROTTLED priority semantics.

net/url_request/url_request_unittest.cc

Index: net/url_request/url_request_unittest.cc
diff --git a/net/url_request/url_request_unittest.cc b/net/url_request/url_request_unittest.cc
index c99852be0d392e6b13226a6aa27fc9770d82da94..e78411e00a46c4011312f49ce0fd12ab52385f61 100644
--- a/net/url_request/url_request_unittest.cc
+++ b/net/url_request/url_request_unittest.cc
@@ -7891,7 +7891,7 @@ TEST_F(URLRequestTestHTTP, NetworkAccessedClearOnLoadOnlyFromCache) {
   EXPECT_FALSE(req->response_info().network_accessed);
 }
 
-// Test that a single job with a throttled priority completes
+// Test that a single job with a THROTTLED priority completes
 // correctly in the absence of contention.
 TEST_F(URLRequestTestHTTP, ThrottledPriority) {
   ASSERT_TRUE(http_test_server()->Start());
@@ -7906,6 +7906,31 @@ TEST_F(URLRequestTestHTTP, ThrottledPriority) {
   EXPECT_TRUE(req->status().is_success());
 }
 
+// Test that three jobs with THROTTLED priorities complete
+// correctly in the absence of contention (the completion of the
+// first one will unthrottle the third, but there is no visibility
+// to that at this level).
+TEST_F(URLRequestTestHTTP, MultiThrottledPriority) {
+  ASSERT_TRUE(http_test_server()->Start());
+
+  TestDelegate d;
+  GURL test_url(http_test_server()->GetURL("/"));
+  std::unique_ptr<URLRequest> req1(
+      default_context_.CreateRequest(test_url, THROTTLED, &d));
+  std::unique_ptr<URLRequest> req2(
+      default_context_.CreateRequest(test_url, THROTTLED, &d));
+  std::unique_ptr<URLRequest> req3(
+      default_context_.CreateRequest(test_url, THROTTLED, &d));
+  req1->Start();
+  req2->Start();
+  req3->Start();
+  base::RunLoop().Run();
+
+  EXPECT_TRUE(req1->status().is_success());
+  EXPECT_TRUE(req2->status().is_success());
+  EXPECT_TRUE(req3->status().is_success());
+}
+
 class URLRequestInterceptorTestHTTP : public URLRequestTestHTTP {
  public:
   // TODO(bengr): Merge this with the URLRequestInterceptorHTTPTest fixture,