Fix missing back navigation item when pending item is displayed.

ios/web/navigation/crw_session_controller_unittest.mm

Index: ios/web/navigation/crw_session_controller_unittest.mm
diff --git a/ios/web/navigation/crw_session_controller_unittest.mm b/ios/web/navigation/crw_session_controller_unittest.mm
index b23a26b5f028a90b09e4f5c02ba2d44d5adf758d..029213e9d33a1838b50f7129bd5135ca6021a596 100644
--- a/ios/web/navigation/crw_session_controller_unittest.mm
+++ b/ios/web/navigation/crw_session_controller_unittest.mm
@@ -1236,4 +1236,57 @@ TEST_F(CRWSessionControllerTest, BackwardItemsForAllRedirects) {
   EXPECT_EQ(0U, [session_controller_ backwardItems].size());
 }
 
+// Tests that |-backwardItems| returns all committed items if there is an
+// uncommitted pending item. This can happend if the pending page loading is
+// intercepted by safe browsing. See crbug.com/691311.
+TEST_F(CRWSessionControllerTest,
+       BackwardItemsShouldContainAllCommittedIfCurrentIsPending) {
+  [session_controller_
+               addPendingItem:GURL("http://www.example.com/0")
+                     referrer:MakeReferrer("http://www.example.com/a")
+                   transition:ui::PAGE_TRANSITION_LINK
+               initiationType:web::NavigationInitiationType::USER_INITIATED
+      userAgentOverrideOption:UserAgentOverrideOption::INHERIT];
+  [session_controller_ commitPendingItem];
+  [session_controller_
+               addPendingItem:GURL("http://www.example.com/1")
+                     referrer:MakeReferrer("http://www.example.com/b")
+                   transition:ui::PAGE_TRANSITION_LINK
+               initiationType:web::NavigationInitiationType::USER_INITIATED
+      userAgentOverrideOption:UserAgentOverrideOption::INHERIT];
+
+  EXPECT_EQ(0, session_controller_.get().lastCommittedItemIndex);
+  EXPECT_TRUE([session_controller_ pendingItem]);
+  EXPECT_EQ(-1, [session_controller_ pendingItemIndex]);
+  EXPECT_EQ(GURL("http://www.example.com/1"), [session_controller_ currentURL]);
+
+  web::NavigationItemList backItems = [session_controller_ backwardItems];

[Eugene But (OOO till 7-30), 2017/04/25 05:49:01]

s/backItems/back_items

https://chromium.googlesource.com/chromium/src/+/master/styleguide/objective-...

[danyao, 2017/04/25 16:31:20]

Done.

[danyao, 2017/04/25 16:31:20]

Oops sorry confused Objective C and JavaScript style guide again... Done.

+  EXPECT_EQ(1U, backItems.size());

[Eugene But (OOO till 7-30), 2017/04/25 05:49:01]

s/EXPECT_EQ/ASSERT_EQ, otherwise line 1265 may crash if vector is empty

[danyao, 2017/04/25 16:31:20]

Done.

[danyao, 2017/04/25 16:31:20]

Done.

+  EXPECT_EQ("http://www.example.com/0", backItems[0]->GetURL().spec());
+}
+
+// Tests that |-backwardItems| returns all committed items if there is a
+// transient item. This can happen if an intersitial was loaded for safe
+// browsing. See crbug.com/691311.
+TEST_F(CRWSessionControllerTest,
+       BackwardItemsShouldContainAllCommittedIfCurrentIsTransient) {
+  [session_controller_
+               addPendingItem:GURL("http://www.example.com/0")
+                     referrer:MakeReferrer("http://www.example.com/a")
+                   transition:ui::PAGE_TRANSITION_LINK
+               initiationType:web::NavigationInitiationType::USER_INITIATED
+      userAgentOverrideOption:UserAgentOverrideOption::INHERIT];
+  [session_controller_ commitPendingItem];
+  [session_controller_
+      addTransientItemWithURL:GURL("http://www.example.com/1")];
+
+  EXPECT_EQ(0, session_controller_.get().lastCommittedItemIndex);
+  EXPECT_TRUE([session_controller_ transientItem]);
+  EXPECT_EQ(GURL("http://www.example.com/1"), [session_controller_ currentURL]);
+
+  web::NavigationItemList backItems = [session_controller_ backwardItems];
+  EXPECT_EQ(1U, backItems.size());
+  EXPECT_EQ("http://www.example.com/0", backItems[0]->GetURL().spec());
+}
+
 }  // anonymous namespace