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..2ba4df5ce99e7a5955d785eea6d3c6ab2574c5d9
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+++ b/ios/chrome/browser/physical_web/physical_web_initial_state_recorder.mm
@@ -0,0 +1,131 @@
+// 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"
+
+#include "base/mac/scoped_nsobject.h"
+#include "base/metrics/histogram.h"
+#include "ios/chrome/browser/physical_web/physical_web_constants.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.

[rohitrao (ping after 24h), 2016/10/31 19:41:08]

This feels very brittle.  There is no better way to encode this information in a
histogram?

[mattreynolds, 2016/11/01 17:17:17]

We could record the state separately, but combining it into one enum makes it
easier for us to tell at a glance which settings are preventing our users from
seeing Physical Web results. We have a similar enum for the Today extension.

+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 {
+  int preferenceState_;
+  BOOL locationServicesEnabled_;
+  BOOL locationAuthorized_;
+  BOOL bluetoothEnabled_;
+  base::scoped_nsobject<CBCentralManager> centralManager_;
+}
+
+- (instancetype)initWithPreferenceState:(int)preferenceState
+                locationServicesEnabled:(BOOL)locationServicesEnabled
+                     locationAuthorized:(BOOL)locationAuthorized {
+  self = [super init];
+  if (self) {
+    preferenceState_ = preferenceState;
+    locationServicesEnabled_ = locationServicesEnabled;
+    locationAuthorized_ = locationAuthorized;
+    centralManager_.reset([[CBCentralManager alloc]
+        initWithDelegate:self
+                   queue:dispatch_get_main_queue()
+                 options:@{
+                   CBCentralManagerOptionShowPowerAlertKey : @NO
+                 }]);
+
+    // Make sure we aren't released before the central manager reports back.
+    [self retain];
+  }
+  return self;
+}
+
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
+- (void)dealloc {
+  [centralManager_ setDelegate:nil];
+  centralManager_.reset();
+  [super dealloc];
+}
+
+- (BOOL)bluetoothEnabled {
+// TODO(crbug.com/619982): The CBManager base class appears to still be in
+// flux.  Unwind this #ifdef once the APIs settle.

[rohitrao (ping after 24h), 2016/10/31 19:41:08]

Have the APIs settled now that iOS10 is out for real?

[mattreynolds, 2016/11/01 17:17:16]

Yeah, I think we can remove the #ifdef now.

+#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
+  return [centralManager_ state] == CBManagerStatePoweredOn;
+#else
+  return [centralManager_ state] == CBCentralManagerStatePoweredOn;
+#endif
+}
+
+- (void)centralManagerDidUpdateState:(CBCentralManager*)central {
+  [self recordInitialStateAndFinish];
+}
+
+- (void)recordInitialStateAndFinish {
+  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 ([self bluetoothEnabled]) {
+    state |= BLUETOOTH_FLAG;
+  }
+
+  DCHECK(state < PHYSICAL_WEB_INITIAL_STATE_COUNT);
+  UMA_HISTOGRAM_ENUMERATION("PhysicalWeb.InitialState.IosChrome", state,
+                            PHYSICAL_WEB_INITIAL_STATE_COUNT);
+
+  [self release];
+}
+
+@end