Collect UMA statistics on which chrome://flags lead to chrome restart on ChromeOS.

chrome/browser/about_flags_unittest.cc

 // Copyright (c) 2011 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/prefs/pref_registry_simple.h"
 #include "base/prefs/testing_pref_service.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/about_flags.h"
@@ skipping 215 matching lines @@
 
   CommandLine command_line2(CommandLine::NO_PROGRAM);
 
   ConvertFlagsToSwitches(&flags_storage_, &command_line2, kNoSentinels);
 
   EXPECT_TRUE(command_line2.HasSwitch(kSwitch1));
   EXPECT_FALSE(command_line2.HasSwitch(switches::kFlagSwitchesBegin));
   EXPECT_FALSE(command_line2.HasSwitch(switches::kFlagSwitchesEnd));
 }
 
+CommandLine::StringType CreateSwitch(const std::string& value) {
+#if defined(OS_WIN)
+  return ASCIIToUTF16(value);
+#else
+  return value;
+#endif
+}
+
 TEST_F(AboutFlagsTest, CompareSwitchesToCurrentCommandLine) {
   SetExperimentEnabled(&flags_storage_, kFlags1, true);
 
+  const std::string kDoubleDash("--");
+
   CommandLine command_line(CommandLine::NO_PROGRAM);
   command_line.AppendSwitch("foo");
 
   CommandLine new_command_line(CommandLine::NO_PROGRAM);
   ConvertFlagsToSwitches(&flags_storage_, &new_command_line, kAddSentinels);
 
-  EXPECT_FALSE(AreSwitchesIdenticalToCurrentCommandLine(new_command_line,
-                                                        command_line));
+  EXPECT_FALSE(AreSwitchesIdenticalToCurrentCommandLine(
+      new_command_line, command_line, NULL));
+  {
+    std::set<CommandLine::StringType> difference;
+    EXPECT_FALSE(AreSwitchesIdenticalToCurrentCommandLine(
+        new_command_line, command_line, &difference));
+    EXPECT_EQ(1U, difference.size());
+    EXPECT_EQ(1U, difference.count(CreateSwitch(kDoubleDash + kSwitch1)));
+  }
 
   ConvertFlagsToSwitches(&flags_storage_, &command_line, kAddSentinels);
 
-  EXPECT_TRUE(AreSwitchesIdenticalToCurrentCommandLine(new_command_line,
-                                                       command_line));
+  EXPECT_TRUE(AreSwitchesIdenticalToCurrentCommandLine(
+      new_command_line, command_line, NULL));
+  {
+    std::set<CommandLine::StringType> difference;
+    EXPECT_TRUE(AreSwitchesIdenticalToCurrentCommandLine(
+        new_command_line, command_line, &difference));
+    EXPECT_TRUE(difference.empty());
+  }
 
   // Now both have flags but different.
   SetExperimentEnabled(&flags_storage_, kFlags1, false);
   SetExperimentEnabled(&flags_storage_, kFlags2, true);
 
   CommandLine another_command_line(CommandLine::NO_PROGRAM);
   ConvertFlagsToSwitches(&flags_storage_, &another_command_line, kAddSentinels);
 
-  EXPECT_FALSE(AreSwitchesIdenticalToCurrentCommandLine(new_command_line,
-                                                        another_command_line));
+  EXPECT_FALSE(AreSwitchesIdenticalToCurrentCommandLine(
+      new_command_line, another_command_line, NULL));
+  {
+    std::set<CommandLine::StringType> difference;
+    EXPECT_FALSE(AreSwitchesIdenticalToCurrentCommandLine(
+        new_command_line, another_command_line, &difference));
+    EXPECT_EQ(2U, difference.size());
+    EXPECT_EQ(1U, difference.count(CreateSwitch(kDoubleDash + kSwitch1)));
+    EXPECT_EQ(1U,
+              difference.count(CreateSwitch(kDoubleDash + kSwitch2 + "=" +
+                                            kValueForSwitch2)));
+  }
 }
 
 TEST_F(AboutFlagsTest, RemoveFlagSwitches) {
   std::map<std::string, CommandLine::StringType> switch_list;
   switch_list[kSwitch1] = CommandLine::StringType();
   switch_list[switches::kFlagSwitchesBegin] = CommandLine::StringType();
   switch_list[switches::kFlagSwitchesEnd] = CommandLine::StringType();
   switch_list["foo"] = CommandLine::StringType();
 
   SetExperimentEnabled(&flags_storage_, kFlags1, true);
@@ skipping 186 matching lines @@
   testing::SetExperiments(NULL, 0);
   size_t count;
   const Experiment* experiments = testing::GetExperiments(&count);
     for (size_t i = 0; i < count; ++i) {
     std::string name = experiments->internal_name;
     EXPECT_EQ(std::string::npos, name.find(testing::kMultiSeparator)) << i;
   }
 }
 
 }  // namespace about_flags