Prerender: Add basic browser tests for Prerender2

This CL adds basic browser tests for <link rel=prerender> using
Prerender2.

Bug: 1132746
Change-Id: I260fb9652839ee30327f5bfd44096ea570aceb9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2489061Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820064}

content/browser/prerender/prerender_browsertest.cc

+// Copyright 2020 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 "base/test/scoped_feature_list.h"
+#include "content/browser/prerender/prerender_host_registry.h"
+#include "content/browser/storage_partition_impl.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/test/browser_test.h"
+#include "content/public/test/browser_test_utils.h"
+#include "content/public/test/content_browser_test.h"
+#include "content/public/test/content_browser_test_utils.h"
+#include "content/public/test/test_navigation_observer.h"
+#include "content/shell/browser/shell.h"
+#include "net/dns/mock_host_resolver.h"
+#include "net/test/embedded_test_server/embedded_test_server.h"
+#include "net/test/embedded_test_server/http_request.h"
+#include "third_party/blink/public/common/features.h"
+
+namespace content {
+namespace {
+
+class PrerenderBrowserTest : public ContentBrowserTest {
+ public:
+  PrerenderBrowserTest() {
+    feature_list_.InitAndEnableFeature(blink::features::kPrerender2);
+  }
+  ~PrerenderBrowserTest() override = default;
+
+  void SetUpOnMainThread() override {
+    host_resolver()->AddRule("*", "127.0.0.1");
+    ssl_server_.AddDefaultHandlers(GetTestDataFilePath());
+    ssl_server_.SetSSLConfig(
+        net::test_server::EmbeddedTestServer::CERT_TEST_NAMES);
+    ssl_server_.RegisterRequestMonitor(base::BindRepeating(
+        &PrerenderBrowserTest::MonitorResourceRequest, base::Unretained(this)));
+    ASSERT_TRUE(ssl_server_.Start());
+  }
+
+  void TearDownOnMainThread() override {
+    EXPECT_TRUE(ssl_server_.ShutdownAndWaitUntilComplete());
+  }
+
+  void MonitorResourceRequest(const net::test_server::HttpRequest& request) {
+    request_count_by_path_[request.GetURL().PathForRequest()]++;
+  }
+
+  PrerenderHostRegistry& GetPrerenderHostRegistry() {
+    auto* storage_partition = static_cast<StoragePartitionImpl*>(
+        BrowserContext::GetDefaultStoragePartition(
+            shell()->web_contents()->GetBrowserContext()));
+    return *storage_partition->GetPrerenderHostRegistry();
+  }
+
+  GURL GetUrl(const std::string& path) {
+    return ssl_server_.GetURL("a.test", path);
+  }
+
+  int GetRequestCount(const GURL& url) {
+    return request_count_by_path_[url.PathForRequest()];
+  }
+
+ private:
+  net::test_server::EmbeddedTestServer ssl_server_{
+      net::test_server::EmbeddedTestServer::TYPE_HTTPS};
+
+  // Counts of requests sent to the server. Keyed by path (not by full URL)
+  // because the host part of the requests is translated ("a.test" to
+  // "127.0.0.1") before the server handles them.
+  std::map<std::string, int> request_count_by_path_;
+
+  base::test::ScopedFeatureList feature_list_;
+};
+
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, LinkRelPrerender) {
+  const GURL kPrerenderingUrl = GetUrl("/empty.html");
+
+  // Start watching new web contents to be created for prerendering.
+  content::TestNavigationObserver navigation_observer(kPrerenderingUrl);
+  navigation_observer.StartWatchingNewWebContents();
+
+  // Navigate to a page that initiates prerendering for `kPrerenderingUrl`.
+  ASSERT_TRUE(
+      NavigateToURL(shell(), GetUrl("/prerender/single_prerender.html")));
+
+  // Wait until the completion of prerendering.
+  navigation_observer.Wait();
+
+  // Check if a request is issued for `kPrerenderingUrl`.
+  EXPECT_EQ(GetRequestCount(kPrerenderingUrl), 1);
+
+  // Check if PrerenderHost for `kPrerenderingUrl` is registered in
+  // PrerenderHostRegistry.
+  PrerenderHostRegistry& registry = GetPrerenderHostRegistry();
+  EXPECT_NE(registry.FindHostByUrl(kPrerenderingUrl), nullptr);
+
+  // TODO(https://crbug.com/1132746): Test navigation to the prerendered page.
+}
+
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, LinkRelPrerender_Multiple) {
+  const GURL kPrerenderingUrl1 = GetUrl("/empty.html?1");
+  const GURL kPrerenderingUrl2 = GetUrl("/empty.html?2");
+
+  // Start watching new web contents to be created for prerendering.
+  content::TestNavigationObserver navigation_observer1(kPrerenderingUrl1);
+  content::TestNavigationObserver navigation_observer2(kPrerenderingUrl2);
+  navigation_observer1.StartWatchingNewWebContents();
+  navigation_observer2.StartWatchingNewWebContents();
+
+  // Navigate to a page that initiates prerendering for `kPrerenderingUrl1` and
+  // `kPrerenderingUrl2`.
+  ASSERT_TRUE(
+      NavigateToURL(shell(), GetUrl("/prerender/multiple_prerenders.html")));
+
+  // Wait until the completion of prerendering.
+  navigation_observer1.Wait();
+  navigation_observer2.Wait();
+
+  // Check if requests are issued for `kPrerenderingUrl1` and
+  // `kPrerenderingUrl2`.
+  EXPECT_EQ(GetRequestCount(kPrerenderingUrl1), 1);
+  EXPECT_EQ(GetRequestCount(kPrerenderingUrl2), 1);
+
+  // Check if PrerenderHosts for `kPrerenderingUrl1` and `kPrerenderingUrl2` are
+  // registered in PrerenderHostRegistry.
+  PrerenderHostRegistry& registry = GetPrerenderHostRegistry();
+  EXPECT_NE(registry.FindHostByUrl(kPrerenderingUrl1), nullptr);
+  EXPECT_NE(registry.FindHostByUrl(kPrerenderingUrl2), nullptr);
+
+  // TODO(https://crbug.com/1132746): Test navigation to one of the prerendered
+  // pages.
+}
+
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, LinkRelPrerender_Duplicate) {
+  const GURL kPrerenderingUrl1 = GetUrl("/empty.html?1");
+  const GURL kPrerenderingUrl2 = GetUrl("/empty.html?2");
+
+  // Start watching new web contents to be created for prerendering.
+  content::TestNavigationObserver navigation_observer1(kPrerenderingUrl1);
+  content::TestNavigationObserver navigation_observer2(kPrerenderingUrl2);
+  navigation_observer1.StartWatchingNewWebContents();
+  navigation_observer2.StartWatchingNewWebContents();
+
+  // Navigate to a page that initiates prerendering for `kPrerenderingUrl1`
+  // twice. The second prerendering request should be ignored.
+  ASSERT_TRUE(
+      NavigateToURL(shell(), GetUrl("/prerender/duplicate_prerenders.html")));
+
+  // Wait until the completion of prerendering.
+  navigation_observer1.Wait();
+  navigation_observer2.Wait();
+
+  // Check if requests are issued once per prerendering URL.
+  EXPECT_EQ(GetRequestCount(kPrerenderingUrl1), 1);
+  EXPECT_EQ(GetRequestCount(kPrerenderingUrl2), 1);
+
+  // Check if PrerenderHosts for `kPrerenderingUrl1` and `kPrerenderingUrl2` are
+  // registered in PrerenderHostRegistry.
+  PrerenderHostRegistry& registry = GetPrerenderHostRegistry();
+  EXPECT_NE(registry.FindHostByUrl(kPrerenderingUrl1), nullptr);
+  EXPECT_NE(registry.FindHostByUrl(kPrerenderingUrl2), nullptr);
+
+  // TODO(https://crbug.com/1132746): Test navigation to the prerendered page.
+}
+
+// TODO(https://crbug.com/1132746): Test canceling prerendering.
+
+// TODO(https://crbug.com/1132746): Test prerendering for 404 page, redirection,
+// auth error, cross origin, etc.
+
+}  // namespace
+}  // namespace content

content/test/BUILD.gn

@@ -1057,6 +1057,7 @@ test("content_browsertests") {
     "../browser/portal/portal_browsertest.cc",
     "../browser/portal/portal_navigation_throttle_browsertest.cc",
     "../browser/power_monitor_browsertest.cc",
+    "../browser/prerender/prerender_browsertest.cc",
     "../browser/process_internals/process_internals_browsertest.cc",
     "../browser/renderer_host/ancestor_throttle_browsertest.cc",
     "../browser/renderer_host/back_forward_cache_metrics_browsertest.cc",

content/test/data/prerender/duplicate_prerenders.html

+<!DOCTYPE html>
+<html>
+<head>
+<title>Duplicate Prerenders Test</title>
+<link rel="prerender" href="/empty.html?1">
+<link rel="prerender" href="/empty.html?1">
+<link rel="prerender" href="/empty.html?2">
+</head>
+<body></body>
+</html>

content/test/data/prerender/multiple_prerenders.html

+<!DOCTYPE html>
+<html>
+<head>
+<title>Multiple Prerenders Test</title>
+<link rel="prerender" href="/empty.html?1">
+<link rel="prerender" href="/empty.html?2">
+</head>
+<body></body>
+</html>

content/test/data/prerender/single_prerender.html

+<!DOCTYPE html>
+<html>
+<head>
+<title>Single Prerender Test</title>
+<link rel="prerender" href="/empty.html">
+</head>
+<body></body>
+</html>