Fix flaky test ContentSerializedNavigationBuilderTest.ToNavigationEntry

components/sessions/content/content_serialized_navigation_builder_unittest.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 "components/sessions/content/content_serialized_navigation_builder.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/sessions/content/content_record_password_state.h"
 #include "components/sessions/content/content_serialized_navigation_driver.h"
@@ skipping 69 matching lines @@
   redirect_chain.push_back(test_data::kVirtualURL);
   navigation_entry->SetRedirectChain(redirect_chain);
   return navigation_entry;
 }
 
 void SetExtendedInfoForTest(content::NavigationEntry* entry) {
   entry->SetExtraData(kExtendedInfoKey1,
                       base::ASCIIToUTF16(kExtendedInfoValue1));
   entry->SetExtraData(kExtendedInfoKey2,
                       base::ASCIIToUTF16(kExtendedInfoValue2));
-  ContentSerializedNavigationDriver::GetInstance()->RegisterExtendedInfoHandler(
-      kExtendedInfoKey1, base::WrapUnique<ExtendedInfoHandler>(
-                             new TestExtendedInfoHandler(kExtendedInfoKey1)));
-  ContentSerializedNavigationDriver::GetInstance()->RegisterExtendedInfoHandler(
-      kExtendedInfoKey2, base::WrapUnique<ExtendedInfoHandler>(
-                             new TestExtendedInfoHandler(kExtendedInfoKey2)));
 }
 
 }  // namespace
 
+class ContentSerializedNavigationBuilderTest : public testing::Test {
+ public:
+  ContentSerializedNavigationBuilderTest() {}
+  ~ContentSerializedNavigationBuilderTest() override {}
+
+  static void SetUpTestCase() {
+    ContentSerializedNavigationDriver::GetInstance()->

[sky, 2016/10/06 17:01:47]

While this works for your test, it means any other test that runs after yours
gets state your test installed. I would prefer you add a reset function on
ContentSerializedNavigationDriver that is private and friended by this test that
clears the map on setup/teardown.

[jianli, 2016/10/06 23:54:50]

Done.

+    RegisterExtendedInfoHandler(
+        kExtendedInfoKey1,
+        base::WrapUnique<ExtendedInfoHandler>(
+            new TestExtendedInfoHandler(kExtendedInfoKey1)));
+    ContentSerializedNavigationDriver::GetInstance()->
+    RegisterExtendedInfoHandler(
+        kExtendedInfoKey2,
+        base::WrapUnique<ExtendedInfoHandler>(
+            new TestExtendedInfoHandler(kExtendedInfoKey2)));
+  }
+};
 
 // Create a SerializedNavigationEntry from a NavigationEntry.  All its fields
 // should match the NavigationEntry's.
-TEST(ContentSerializedNavigationBuilderTest, FromNavigationEntry) {
+TEST_F(ContentSerializedNavigationBuilderTest, FromNavigationEntry) {
   const std::unique_ptr<content::NavigationEntry> navigation_entry(
       MakeNavigationEntryForTest());
   SetExtendedInfoForTest(navigation_entry.get());
 
   const SerializedNavigationEntry& navigation =
       ContentSerializedNavigationBuilder::FromNavigationEntry(
           test_data::kIndex, *navigation_entry);
 
   EXPECT_EQ(test_data::kIndex, navigation.index());
 
@@ skipping 25 matching lines @@
             navigation.extended_info_map().at(kExtendedInfoKey1));
   ASSERT_EQ(1U, navigation.extended_info_map().count(kExtendedInfoKey2));
   EXPECT_EQ(kExtendedInfoValue2,
             navigation.extended_info_map().at(kExtendedInfoKey2));
 }
 
 // Create a NavigationEntry, then create another one by converting to
 // a SerializedNavigationEntry and back.  The new one should match the old one
 // except for fields that aren't preserved, which should be set to
 // expected values.
-TEST(ContentSerializedNavigationBuilderTest, ToNavigationEntry) {
+TEST_F(ContentSerializedNavigationBuilderTest, ToNavigationEntry) {
   const std::unique_ptr<content::NavigationEntry> old_navigation_entry(
       MakeNavigationEntryForTest());
   SetExtendedInfoForTest(old_navigation_entry.get());
 
   const SerializedNavigationEntry& navigation =
       ContentSerializedNavigationBuilder::FromNavigationEntry(
           test_data::kIndex, *old_navigation_entry);
 
   const std::unique_ptr<content::NavigationEntry> new_navigation_entry(
       ContentSerializedNavigationBuilder::ToNavigationEntry(
@@ skipping 30 matching lines @@
 
   base::string16 extra_data;
   EXPECT_TRUE(
       new_navigation_entry->GetExtraData(kExtendedInfoKey1, &extra_data));
   EXPECT_EQ(kExtendedInfoValue1, base::UTF16ToASCII(extra_data));
   EXPECT_TRUE(
       new_navigation_entry->GetExtraData(kExtendedInfoKey2, &extra_data));
   EXPECT_EQ(kExtendedInfoValue2, base::UTF16ToASCII(extra_data));
 }
 
-TEST(ContentSerializedNavigationBuilderTest, SetPasswordState) {
+TEST_F(ContentSerializedNavigationBuilderTest, SetPasswordState) {
   std::unique_ptr<content::NavigationEntry> entry(
       content::NavigationEntry::Create());
 
   EXPECT_EQ(SerializedNavigationEntry::PASSWORD_STATE_UNKNOWN,
             GetPasswordStateFromNavigation(*entry));
   SetPasswordStateInNavigation(SerializedNavigationEntry::NO_PASSWORD_FIELD,
                                entry.get());
   EXPECT_EQ(SerializedNavigationEntry::NO_PASSWORD_FIELD,
             GetPasswordStateFromNavigation(*entry));
 }
 
 }  // namespace sessions