Cache the Windows Parental Controls Platform Answer

chrome/browser/prefs/incognito_mode_prefs.cc

 // Copyright (c) 2012 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 "chrome/browser/prefs/incognito_mode_prefs.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 
 #if defined(OS_WIN)
 #include "base/win/metro.h"
 #endif  // OS_WIN
 
 #if defined(OS_ANDROID)
 #include "chrome/browser/android/chromium_application.h"
 #endif  // OS_ANDROID
 
 #if defined(OS_WIN)
 namespace {
 
-bool g_parental_control_on = false;
+// Possible values for the parental controls state.
+enum ParentalControlsState {

[gab, 2015/02/25 20:23:52]

Consider using C++11 enum class, (I typically prefer them for the extra type
safety provided).

Also, since the enum becomes an explicit namespace, you can shorten the enum
values (e.g., UNINITIALIZED, DISABLED, ENABLED).

[robliao, 2015/02/26 21:03:51]

Done.

+  // Parental controls state unknown. We have not queried for this value yet.
+  PARENTAL_CONTROLS_STATE_UNKNOWN = 0,
+  // Parental controls activity logging disabled.
+  ACTIVITY_LOGGING_DISABLED = 1,
+  // Parental controls activity logging enabled.
+  ACTIVITY_LOGGING_ENABLED = 2,
+};
+ParentalControlsState g_parental_controls_state =

[gab, 2015/02/25 20:23:51]

Merge with end of enum instead of re-declaring type, e.g.:

enum {
 ...
} g_parental_controls_state = PARENTAL_CONTROLS_STATE_UNKNOWN;

[robliao, 2015/02/26 21:03:51]

There aren't many enum declarations that use this style, so we should probably
keep it as is:
https://code.google.com/p/chromium/codesearch#search/&q=%5E%7D%5C%20.%2B%5C%2...

[gab, 2015/03/02 17:09:24]

Ah interesting, expanded regex a bit, found 15 instances in src/. I don't think
it applies in many situations, but I think this is a good example of where it
could (i.e. this variable is declared right after and is the only one of that
type in this file -- as highlighted by the lack of an empty line between the
two, these two really go together).

https://code.google.com/p/chromium/codesearch#search/&q=%5B%5Cs%5D*%7D%5C%20(...

+    PARENTAL_CONTROLS_STATE_UNKNOWN;
 
 } // empty namespace
 #endif  // OS_WIN
 
 // static
 bool IncognitoModePrefs::IntToAvailability(int in_value,
                                            Availability* out_value) {
   if (in_value < 0 || in_value >= AVAILABILITY_NUM_TYPES) {
     *out_value = ENABLED;
     return false;
   }
   *out_value = static_cast<Availability>(in_value);
   return true;
 }
 
 // static
 IncognitoModePrefs::Availability IncognitoModePrefs::GetAvailability(
     const PrefService* pref_service) {
   DCHECK(pref_service);
   int pref_value = pref_service->GetInteger(prefs::kIncognitoModeAvailability);
   Availability result = IncognitoModePrefs::ENABLED;
   bool valid = IntToAvailability(pref_value, &result);
   DCHECK(valid);
-  if (ArePlatformParentalControlsEnabled()) {
+  if (ArePlatformParentalControlsEnabledCached()) {
     if (result == IncognitoModePrefs::FORCED)
       LOG(ERROR) << "Ignoring FORCED incognito. Parental control logging on";
     return IncognitoModePrefs::DISABLED;
   }
   return result;
 }
 
 // static
 void IncognitoModePrefs::SetAvailability(PrefService* prefs,
                                          const Availability availability) {
@@ skipping 33 matching lines @@
 
     case IncognitoModePrefs::FORCED:
       return profile->IsOffTheRecord();
 
     default:
       NOTREACHED();
       return false;
   }
 }
 
-// static
-bool IncognitoModePrefs::ArePlatformParentalControlsEnabled() {
-#if defined(OS_WIN)
-  // Disable incognito mode windows if parental controls are on. This is only
-  // for Windows Vista and above.
-  return base::win::IsParentalControlActivityLoggingOn();
-#elif defined(OS_ANDROID)
-  return chrome::android::ChromiumApplication::AreParentalControlsEnabled();
-#else
-  return false;
-#endif
-}
-
 #if defined(OS_WIN)
 void IncognitoModePrefs::InitializePlatformParentalControls() {
-  g_parental_control_on = base::win::IsParentalControlActivityLoggingOn();
+  g_parental_controls_state =
+      base::win::IsParentalControlActivityLoggingOn() ?
+      ACTIVITY_LOGGING_ENABLED :
+      ACTIVITY_LOGGING_DISABLED;
 }
 #endif // OS_WIN
 
 bool IncognitoModePrefs::ArePlatformParentalControlsEnabledCached() {
 #if defined(OS_WIN)
-  return g_parental_control_on;
+  DCHECK(g_parental_controls_state != PARENTAL_CONTROLS_STATE_UNKNOWN);
+  return g_parental_controls_state == ACTIVITY_LOGGING_ENABLED;
 #elif defined(OS_ANDROID)
   return chrome::android::ChromiumApplication::AreParentalControlsEnabled();
 #else
   return false;
 #endif
 }