Record the initial state of the Physical Web at startup

ios/chrome/browser/physical_web/physical_web_initial_state_recorder.mm

Index: ios/chrome/browser/physical_web/physical_web_initial_state_recorder.mm
diff --git a/ios/chrome/browser/physical_web/physical_web_initial_state_recorder.mm b/ios/chrome/browser/physical_web/physical_web_initial_state_recorder.mm
new file mode 100644
index 0000000000000000000000000000000000000000..29b23cf3987cc292ebf9f7539bbc1a0035c771fd
--- /dev/null
+++ b/ios/chrome/browser/physical_web/physical_web_initial_state_recorder.mm
@@ -0,0 +1,150 @@
+// Copyright 2016 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.
+
+#import "ios/chrome/browser/physical_web/physical_web_initial_state_recorder.h"
+
+#import <CoreBluetooth/CoreBluetooth.h>
+#import <CoreLocation/CoreLocation.h>
+
+#include "base/mac/scoped_nsobject.h"
+#include "base/metrics/histogram.h"
+#include "components/prefs/pref_service.h"
+#include "ios/chrome/browser/physical_web/physical_web_constants.h"
+#include "ios/chrome/browser/pref_names.h"
+
+namespace {
+
+// Initial state of settings relevant to the Physical Web feature. These are
+// ordered so that bits 2:0 encode the Bluetooth enabled state, the Location
+// Services enabled state, and whether Chrome has been granted the Location app
+// permission. Bits 4:3 encode the Physical Web preference tristate.

[Olivier, 2016/11/10 18:08:08]

Can you add that this enum is used in histogram and should not be reorder or
states removed?

[mattreynolds, 2016/11/11 02:26:10]

Done.

+enum PhysicalWebInitialStateIosChrome {
+  OPTOUT_BTOFF_LOCOFF_UNAUTH,
+  OPTOUT_BTOFF_LOCOFF_AUTH,
+  OPTOUT_BTOFF_LOCON_UNAUTH,
+  OPTOUT_BTOFF_LOCON_AUTH,
+  OPTOUT_BTON_LOCOFF_UNAUTH,
+  OPTOUT_BTON_LOCOFF_AUTH,
+  OPTOUT_BTON_LOCON_UNAUTH,
+  OPTOUT_BTON_LOCON_AUTH,
+  OPTIN_BTOFF_LOCOFF_UNAUTH,
+  OPTIN_BTOFF_LOCOFF_AUTH,
+  OPTIN_BTOFF_LOCON_UNAUTH,
+  OPTIN_BTOFF_LOCON_AUTH,
+  OPTIN_BTON_LOCOFF_UNAUTH,
+  OPTIN_BTON_LOCOFF_AUTH,
+  OPTIN_BTON_LOCON_UNAUTH,
+  OPTIN_BTON_LOCON_AUTH,
+  ONBOARDING_BTOFF_LOCOFF_UNAUTH,
+  ONBOARDING_BTOFF_LOCOFF_AUTH,
+  ONBOARDING_BTOFF_LOCON_UNAUTH,
+  ONBOARDING_BTOFF_LOCON_AUTH,
+  ONBOARDING_BTON_LOCOFF_UNAUTH,
+  ONBOARDING_BTON_LOCOFF_AUTH,
+  ONBOARDING_BTON_LOCON_UNAUTH,
+  ONBOARDING_BTON_LOCON_AUTH,
+  PHYSICAL_WEB_INITIAL_STATE_COUNT,
+
+  // Helper flag values
+  LOCATION_AUTHORIZED_FLAG = 1 << 0,
+  LOCATION_SERVICES_FLAG = 1 << 1,
+  BLUETOOTH_FLAG = 1 << 2,
+  OPTIN_FLAG = 1 << 3,
+  ONBOARDING_FLAG = 1 << 4,
+};
+}  // namespace
+
+@implementation PhysicalWebInitialStateRecorder {
+  PrefService* prefService_;
+  BOOL recordedState_;
+  base::scoped_nsobject<CBCentralManager> centralManager_;
+}
+
+- (instancetype)initWithPrefService:(PrefService*)prefService {
+  self = [super init];
+  if (self) {
+    prefService_ = prefService;

[rohitrao (ping after 24h), 2016/11/10 13:01:44]

Instead of caching the prefService, could you extract the values you need and
save those instead?  That would reduce the risk of the PrefService going away
while the bluetooth check is in progress.

[mattreynolds, 2016/11/11 02:26:10]

Done.

+  }
+  return self;
+}
+
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
+- (void)dealloc {
+  [centralManager_ setDelegate:nil];
+  centralManager_.reset();
+  [super dealloc];
+}
+
+- (void)centralManagerDidUpdateState:(CBCentralManager*)central {
+  // Remove ourselves as a delegate so we won't get notified for later changes
+  // to the Bluetooth enabled state.
+  [centralManager_ setDelegate:nil];
+
+  int preferenceState = prefService_->GetInteger(prefs::kIosPhysicalWebEnabled);
+
+  BOOL bluetoothEnabled = [centralManager_ state] == CBManagerStatePoweredOn;
+
+  BOOL locationServicesEnabled = [CLLocationManager locationServicesEnabled];
+
+  CLAuthorizationStatus authStatus = [CLLocationManager authorizationStatus];
+  BOOL locationAuthorized =
+      authStatus == kCLAuthorizationStatusAuthorizedWhenInUse ||
+      authStatus == kCLAuthorizationStatusAuthorizedAlways;
+
+  [self recordStateWithPreferenceState:preferenceState
+                      bluetoothEnabled:bluetoothEnabled
+               locationServicesEnabled:locationServicesEnabled
+                    locationAuthorized:locationAuthorized];
+}
+
+- (void)collectAndRecordState {
+  if (recordedState_) {
+    return;
+  }
+  recordedState_ = YES;
+
+  // The Bluetooth enabled state must be checked asynchronously. When the state
+  // is ready, it will call our centralManagerDidUpdateState method.
+  centralManager_.reset([[CBCentralManager alloc]
+      initWithDelegate:self
+                 queue:dispatch_get_main_queue()
+               options:@{
+                 // By default, creating a CBCentralManager object with
+                 // Bluetooth disabled will prompt the user to enable Bluetooth.
+                 // Passing ShowPowerAlert=NO disables the prompt so we can
+                 // check the Bluetooth enabled state silently.
+                 CBCentralManagerOptionShowPowerAlertKey : @NO
+               }]);
+}
+
+- (void)recordStateWithPreferenceState:(int)preferenceState
+                      bluetoothEnabled:(BOOL)bluetoothEnabled
+               locationServicesEnabled:(BOOL)locationServicesEnabled
+                    locationAuthorized:(BOOL)locationAuthorized {
+  int state = 0;
+  if (preferenceState == physical_web::kPhysicalWebOn) {
+    state |= OPTIN_FLAG;
+  } else if (preferenceState == physical_web::kPhysicalWebOnboarding) {
+    state |= ONBOARDING_FLAG;
+  }
+  if (locationServicesEnabled) {
+    state |= LOCATION_SERVICES_FLAG;
+  }
+  if (locationAuthorized) {
+    state |= LOCATION_AUTHORIZED_FLAG;
+  }
+  if (bluetoothEnabled) {
+    state |= BLUETOOTH_FLAG;
+  }
+
+  DCHECK(state < PHYSICAL_WEB_INITIAL_STATE_COUNT);
+  UMA_HISTOGRAM_ENUMERATION("PhysicalWeb.InitialState.IosChrome", state,
+                            PHYSICAL_WEB_INITIAL_STATE_COUNT);
+}
+
+@end