prerender: Add a same-site cross-origin speculation tags test

This CL adds a test verifying speculation rules tags header field is
sent in same-site cross-origin situation.

See the section in the related spec:
https://github.com/WICG/nav-speculation/blob/main/speculation-rules-tags.md#the-cross-site-case

Bug: 381687257
Change-Id: I4aa56054934c7a132dcee460fe099e804b4833c4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6433267
Commit-Queue: Huanpo Lin <robertlin@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Domenic Denicola <domenic@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1444507}

content/browser/preloading/prerender/prerender_browsertest.cc

@@ -428,12 +428,20 @@ class PrerenderBrowserTest : public ContentBrowserTest,
     return prerender_helper_->AddPrerender(prerendering_url, world_id);
   }
 
+  FrameTreeNodeId AddPrerenderWithTags(const GURL& prerendering_url,
+                                       std::optional<std::string> tag) {
+    return prerender_helper_->AddPrerender(
+        prerendering_url, /*eagerness=*/std::nullopt,
+        /*no_vary_search_hint=*/std::string(),
+        /*target_hint=*/std::string(), tag);
+  }
+
   FrameTreeNodeId AddPrerender(const GURL& prerendering_url,
                                std::string no_vary_search_hint,
                                int32_t world_id = ISOLATED_WORLD_ID_GLOBAL) {
     return prerender_helper_->AddPrerender(
         prerendering_url, /*eagerness=*/std::nullopt, no_vary_search_hint,
-        /*target_hint=*/std::string(), world_id);
+        /*target_hint=*/std::string(), /*ruleset_tag=*/std::nullopt, world_id);
   }
 
   void AddPrerenderAsync(const GURL& prerendering_url) {
@@ -12775,6 +12783,26 @@ IN_PROC_BROWSER_TEST_P(PrerenderRequestHeadersBrowserTest,
   }
 }
 
+IN_PROC_BROWSER_TEST_P(PrerenderRequestHeadersBrowserTest,
+                       SpeculationRulesTagForSameSiteCrossOrigin) {
+  const GURL initial_url = GetUrl("/prerender/empty.html");
+  const GURL prerender_url =
+      GetSameSiteCrossOriginUrl("/prerender/prerender_with_opt_in_header.html");
+
+  // Navigate to an initial page.
+  ASSERT_TRUE(NavigateToURL(shell(), initial_url));
+  FrameTreeNodeId host_id = AddPrerenderWithTags(prerender_url, "tag1");
+  auto* prerendered_rfh = GetPrerenderedMainFrameHost(host_id);
+  EXPECT_TRUE(prerendered_rfh != nullptr);
+
+  if (IsSpeculationRulesTagsEnabled()) {
+    EXPECT_TRUE(HasSecSpeculationTagsHeader(prerender_url));
+    EXPECT_EQ(GetSecSpeculationTagsHeader(prerender_url), "\"tag1\"");
+  } else {
+    EXPECT_FALSE(HasSecSpeculationTagsHeader(prerender_url));
+  }
+}
+
 // This prefetch test is tentatively implemented here to reuse the test infra.
 // TODO(crbug.com/381687257): Move this test to prefetch browser tests.
 IN_PROC_BROWSER_TEST_P(PrerenderRequestHeadersBrowserTest, Prefetch) {

content/public/test/prerender_test_util.cc

@@ -40,6 +40,16 @@ constexpr char kAddSpeculationRuleScript[] = R"({
     document.head.appendChild(script);
   })";
 
+constexpr char kAddSpeculationRuleWithRulesetTagScript[] = R"({
+    const script = document.createElement('script');
+    script.type = 'speculationrules';
+    script.text = `{
+      "tag": "$1",
+      "prerender": [{ $2 }]
+    }`;
+    document.head.appendChild(script);
+  })";
+
 std::string ConvertEagernessToString(
     blink::mojom::SpeculationEagerness eagerness) {
   switch (eagerness) {
@@ -57,7 +67,8 @@ std::string BuildScriptElementSpeculationRules(
     const std::vector<GURL>& prerendering_urls,
     std::optional<blink::mojom::SpeculationEagerness> eagerness,
     std::optional<std::string> no_vary_search_hint,
-    const std::string& target_hint) {
+    const std::string& target_hint,
+    std::optional<std::string> ruleset_tag) {
   std::stringstream ss;
 
   // Add source filed.
@@ -92,8 +103,12 @@ std::string BuildScriptElementSpeculationRules(
     ss << base::StringPrintf(R"(, "target_hint": "%s")", target_hint.c_str());
   }
 
-  return base::ReplaceStringPlaceholders(kAddSpeculationRuleScript, {ss.str()},
+  return ruleset_tag.has_value()
-                                         nullptr);
+             ? base::ReplaceStringPlaceholders(
+                   kAddSpeculationRuleWithRulesetTagScript,
+                   {ruleset_tag.value(), ss.str()}, nullptr)
+             : base::ReplaceStringPlaceholders(kAddSpeculationRuleScript,
+                                               {ss.str()}, nullptr);
 }
 
 constexpr char kAddSpeculationRulePrefetchScript[] = R"({
@@ -549,7 +564,7 @@ FrameTreeNodeId PrerenderTestHelper::AddPrerender(
     int32_t world_id) {
   return AddPrerender(prerendering_url, eagerness,
                       /*no_vary_search_hint=*/std::nullopt, target_hint,
-                      world_id);
+                      /*ruleset_tag=*/std::nullopt, world_id);
 }
 
 FrameTreeNodeId PrerenderTestHelper::AddPrerender(
@@ -557,6 +572,7 @@ FrameTreeNodeId PrerenderTestHelper::AddPrerender(
     std::optional<blink::mojom::SpeculationEagerness> eagerness,
     std::optional<std::string> no_vary_search_hint,
     const std::string& target_hint,
+    std::optional<std::string> ruleset_tag,
     int32_t world_id) {
   TRACE_EVENT("test", "PrerenderTestHelper::AddPrerender", "prerendering_url",
               prerendering_url);
@@ -573,14 +589,14 @@ FrameTreeNodeId PrerenderTestHelper::AddPrerender(
           run_loop.QuitClosure().Run();
         }));
     AddPrerendersAsync({prerendering_url}, eagerness, no_vary_search_hint,
-                       target_hint, world_id);
+                       target_hint, ruleset_tag, world_id);
     run_loop.Run();
   } else {
     // For other target hints, the initiator's WebContents will host a
     // prerendered page.
     prerender_web_contents = GetWebContents();
     AddPrerendersAsync({prerendering_url}, eagerness, no_vary_search_hint,
-                       target_hint, world_id);
+                       target_hint, ruleset_tag, world_id);
   }
 
   WaitForPrerenderLoadCompletion(*prerender_web_contents, prerendering_url);
@@ -602,7 +618,7 @@ void PrerenderTestHelper::AddPrerendersAsync(
     int32_t world_id) {
   AddPrerendersAsync(prerendering_urls, eagerness,
                      /*no_vary_search_hint=*/std::nullopt, target_hint,
-                     world_id);
+                     /*ruleset_tag=*/std::nullopt, world_id);
 }
 
 void PrerenderTestHelper::AddPrerendersAsync(
@@ -610,6 +626,7 @@ void PrerenderTestHelper::AddPrerendersAsync(
     std::optional<blink::mojom::SpeculationEagerness> eagerness,
     std::optional<std::string> no_vary_search_hint,
     const std::string& target_hint,
+    std::optional<std::string> ruleset_tag,
     int32_t world_id) {
   TRACE_EVENT(
       "test", "PrerenderTestHelper::AddPrerendersAsync", "prerendering_urls",
@@ -621,7 +638,8 @@ void PrerenderTestHelper::AddPrerendersAsync(
       "target_hint", target_hint.empty() ? "(empty)" : target_hint);
   EXPECT_TRUE(content::BrowserThread::CurrentlyOn(BrowserThread::UI));
   std::string script = BuildScriptElementSpeculationRules(
-      prerendering_urls, eagerness, no_vary_search_hint, target_hint);
+      prerendering_urls, eagerness, no_vary_search_hint, target_hint,
+      ruleset_tag);
 
   if (world_id == ISOLATED_WORLD_ID_GLOBAL) {
     // Have to use ExecuteJavaScriptForTests instead of ExecJs/EvalJs here,

content/public/test/prerender_test_util.h

@@ -186,6 +186,7 @@ class PrerenderTestHelper {
       std::optional<blink::mojom::SpeculationEagerness> eagerness,
       std::optional<std::string> no_vary_search_hint,
       const std::string& target_hint,
+      std::optional<std::string> ruleset_tag = std::nullopt,
       int32_t world_id = ISOLATED_WORLD_ID_GLOBAL);
   // AddPrerenderAsync() is the same as AddPrerender(), but does not wait until
   // the completion of prerendering.
@@ -201,6 +202,7 @@ class PrerenderTestHelper {
       std::optional<blink::mojom::SpeculationEagerness> eagerness,
       std::optional<std::string> no_vary_search_hint,
       const std::string& target_hint,
+      std::optional<std::string> ruleset_tag = std::nullopt,
       int32_t world_id = ISOLATED_WORLD_ID_GLOBAL);
 
   void AddPrefetchAsync(const GURL& prefetch_url);