[NoStatePrefetch] Don't cancel prefetches when there are duplicates

chrome/browser/prerender/prerender_unittest.cc

Index: chrome/browser/prerender/prerender_unittest.cc
diff --git a/chrome/browser/prerender/prerender_unittest.cc b/chrome/browser/prerender/prerender_unittest.cc
index 82b9e9666d8301ff63c6a55b5f6abbe41db6aefb..73ba4f997e7f41058127e6f5fb22089f11bfc48b 100644
--- a/chrome/browser/prerender/prerender_unittest.cc
+++ b/chrome/browser/prerender/prerender_unittest.cc
@@ -642,6 +642,38 @@ TEST_F(PrerenderTest, DuplicateTest) {
   ASSERT_EQ(prerender_contents, entry.get());
 }
 
+// Make sure that if queue a request, and a second prerender request for the

[mattcary, 2017/01/10 15:00:50]

Maybe say explicitly that this is the same as the previous test except for
NoState.

[droger, 2017/01/10 15:11:42]

Done.

+// same URL comes in, that the second request attaches to the first prerender,
+// and we don't use the second prerender contents.
+TEST_F(PrerenderTest, DuplicateTest_NoStatePrefetch) {
+  RestorePrerenderMode restore_prerender_mode;
+  prerender_manager()->SetMode(
+      PrerenderManager::PRERENDER_MODE_NOSTATE_PREFETCH);
+
+  SetConcurrency(2);
+  GURL url("http://www.google.com/");
+  DummyPrerenderContents* prerender_contents =
+      prerender_manager()->CreateNextPrerenderContents(
+          url,
+          FINAL_STATUS_USED);
+  EXPECT_TRUE(AddSimplePrerender(url));
+  EXPECT_FALSE(prerender_manager()->next_prerender_contents());
+  EXPECT_TRUE(prerender_contents->prerendering_has_started());
+
+  DummyPrerenderContents* prerender_contents1 =
+      prerender_manager()->CreateNextPrerenderContents(
+          url,
+          FINAL_STATUS_MANAGER_SHUTDOWN);
+  EXPECT_TRUE(AddSimplePrerender(url));
+  EXPECT_EQ(prerender_contents1,
+            prerender_manager()->next_prerender_contents());
+  EXPECT_FALSE(prerender_contents1->prerendering_has_started());
+
+  std::unique_ptr<PrerenderContents> entry =
+      prerender_manager()->FindAndUseEntry(url);
+  ASSERT_EQ(prerender_contents, entry.get());
+}
+
 // Ensure that we expire a prerendered page after the max. permitted time.
 TEST_F(PrerenderTest, ExpireTest) {
   base::SimpleTestTickClock* tick_clock =