Ensure that unique ids are unique.

content/browser/frame_host/navigation_controller_impl_browsertest.cc

 // Copyright 2014 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/bind.h"
 #include "base/command_line.h"
 #include "base/strings/stringprintf.h"
 #include "content/browser/frame_host/frame_navigation_entry.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/navigation_controller_impl.h"
@@ skipping 39 matching lines @@
       shell()->web_contents()->GetController();
   // Load data. Blocks until it is done.
   content::LoadDataWithBaseURL(shell(), history_url, data, base_url);
 
   // We should use history_url instead of the base_url as the original url of
   // this navigation entry, because base_url is only used for resolving relative
   // paths in the data, or enforcing same origin policy.
   EXPECT_EQ(controller.GetVisibleEntry()->GetOriginalRequestURL(), history_url);
 }
 
+IN_PROC_BROWSER_TEST_F(NavigationControllerBrowserTest, UniqueIDs) {
+  const NavigationControllerImpl& controller =
+      static_cast<const NavigationControllerImpl&>(
+          shell()->web_contents()->GetController());
+
+  GURL main_url(embedded_test_server()->GetURL(
+      "/navigation_controller/page_with_link_to_load_iframe.html"));
+  NavigateToURL(shell(), main_url);
+  ASSERT_EQ(1, controller.GetEntryCount());
+
+  // Use JavaScript to click the link and load the iframe.
+  std::string script = "document.getElementById('link').click()";
+  EXPECT_TRUE(content::ExecuteScript(shell()->web_contents(), script));
+  EXPECT_TRUE(WaitForLoadStop(shell()->web_contents()));
+  ASSERT_EQ(2, controller.GetEntryCount());
+
+  // Unique IDs should... um... be unique.
+  ASSERT_NE(controller.GetEntryAtIndex(0)->GetUniqueID(),
+            controller.GetEntryAtIndex(1)->GetUniqueID());
+}
+
 // The renderer uses the position in the history list as a clue to whether a
 // navigation is stale. In the case where the entry limit is reached and the
 // history list is pruned, make sure that there is no mismatch that would cause
 // it to start incorrectly rejecting navigations as stale. See
 // http://crbug.com/89798.
 IN_PROC_BROWSER_TEST_F(NavigationControllerBrowserTest,
                        DontIgnoreBackAfterNavEntryLimit) {
   NavigationController& controller =
       shell()->web_contents()->GetController();
 
@@ skipping 1339 matching lines @@
     // tricky.
     EXPECT_EQ(nullptr, controller.GetPendingEntry());
     shell()->web_contents()->Stop();
     watcher.Wait();
   }
 
   ResourceDispatcherHost::Get()->SetDelegate(nullptr);
 }
 
 }  // namespace content