Instrument registration happy path with analytics.

// FREEBIE

Signal/src/ViewControllers/CodeVerificationViewController.m

@@ -260,8 +260,11 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)verifyChallengeAction:(nullable id)sender
 {
     [self startActivityIndicator];
+    OWSProdInfo(@"registration_registering_code");
     [self.accountManager registerWithVerificationCode:[self validationCodeFromTextField]]
         .then(^{
+            OWSProdInfo(@"registration_registered_complete");
+
             DDLogInfo(@"%@ Successfully registered Signal account.", self.tag);
             dispatch_async(dispatch_get_main_queue(), ^{
                 [self stopActivityIndicator];

Signal/src/ViewControllers/RegistrationViewController.m

@@ -52,6 +52,12 @@ NSString *const kKeychainKey_LastRegisteredPhoneNumber = @"kKeychainKey_LastRegi
     [[Environment getCurrent] setSignUpFlowNavigationController:self.navigationController];
 }
 
+- (void)viewDidLoad {
+    [super viewDidLoad];
+    
+    OWSProdInfo(@"registration_began");
+}
+
 - (void)createViews
 {
     self.view.backgroundColor = [UIColor ows_signalBrandBlueColor];
@@ -335,6 +341,8 @@ NSString *const kKeychainKey_LastRegisteredPhoneNumber = @"kKeychainKey_LastRegi
     __weak RegistrationViewController *weakSelf = self;
     [TSAccountManager registerWithPhoneNumber:parsedPhoneNumber
         success:^{
+            OWSProdInfo(@"registration_registered_phone_number");
+
             [weakSelf.spinnerView stopAnimating];
 
             CodeVerificationViewController *vc = [CodeVerificationViewController new];