Add an error page for HTTP 404 error pages without bodies.

chrome/browser/extensions/activity_log/activity_log_browsertest.cc

Index: chrome/browser/extensions/activity_log/activity_log_browsertest.cc
diff --git a/chrome/browser/extensions/activity_log/activity_log_browsertest.cc b/chrome/browser/extensions/activity_log/activity_log_browsertest.cc
index 0598ea86c877d158c7631e93d25ab426d4889cc6..43664e4d6d39a44b0715c407e44148e084777d9e 100644
--- a/chrome/browser/extensions/activity_log/activity_log_browsertest.cc
+++ b/chrome/browser/extensions/activity_log/activity_log_browsertest.cc
@@ -55,11 +55,10 @@ class ActivityLogPrerenderTest : public ExtensionApiTest {
     ASSERT_EQ("[\"/google_cs.js\"]",
               ActivityLogPolicy::Util::Serialize(last->args()));
     ASSERT_EQ(
-        base::StringPrintf("http://www.google.com.bo:%u/test.html", port),
+        base::StringPrintf("http://www.google.com.bo:%u/title1.html", port),

[Devlin, 2016/08/02 16:17:34]

So previously these tried navigating to a nonexistent page, which now fails?

[mmenke, 2016/08/02 16:27:00]

Now when we navigate to an empty 404 page, we show an error page.  Prerenders
are cancelled when they see an error page commit.  Showing a 404 page received
from a server doesn't count as an error page, but if we generate the error page,
it does count as an error page.  May be worth changing behavior there, but
beyond the scope of this CL.

         last->SerializePageUrl());
-    ASSERT_EQ(
-        base::StringPrintf("www.google.com.bo:%u/test.html", port),
-        last->page_title());
+    ASSERT_EQ(base::StringPrintf("www.google.com.bo:%u/title1.html", port),
+              last->page_title());
     ASSERT_EQ("{\"prerender\":true}",
               ActivityLogPolicy::Util::Serialize(last->other()));
     ASSERT_EQ("", last->api_name());
@@ -102,9 +101,7 @@ IN_PROC_BROWSER_TEST_F(ActivityLogPrerenderTest, TestScriptInjected) {
       content::NOTIFICATION_LOAD_STOP,
       content::NotificationService::AllSources());
 
-  GURL url(base::StringPrintf(
-      "http://www.google.com.bo:%u/test.html",
-      port));
+  GURL url(base::StringPrintf("http://www.google.com.bo:%u/title1.html", port));
 
   const gfx::Size kSize(640, 480);
   std::unique_ptr<prerender::PrerenderHandle> prerender_handle(