mac: Add histograms to measure impact of Address Book integration.

components/autofill/core/browser/personal_data_manager_mac.mm

Index: components/autofill/core/browser/personal_data_manager_mac.mm
diff --git a/components/autofill/core/browser/personal_data_manager_mac.mm b/components/autofill/core/browser/personal_data_manager_mac.mm
index 42e517f38d1bbccad25c584f49d20facde02fd65..9054a8198292a547c997595fbca89709d2631540 100644
--- a/components/autofill/core/browser/personal_data_manager_mac.mm
+++ b/components/autofill/core/browser/personal_data_manager_mac.mm
@@ -18,6 +18,7 @@
 #include "base/prefs/pref_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/time/time.h"
 #include "components/autofill/core/browser/autofill_country.h"
 #include "components/autofill/core/browser/autofill_profile.h"
 #include "components/autofill/core/browser/autofill_type.h"
@@ -79,6 +80,7 @@ void RecordAccessSkipped(bool skipped) {
 ABAddressBook* GetAddressBook(PrefService* pref_service) {
   bool first_access = !HasQueriedMacAddressBook(pref_service);
 
+  base::Time start_time = base::Time::Now();
   // +[ABAddressBook sharedAddressBook] throws an exception internally in
   // circumstances that aren't clear. The exceptions are only observed in crash
   // reports, so it is unknown whether they would be caught by AppKit and nil
@@ -88,6 +90,13 @@ ABAddressBook* GetAddressBook(PrefService* pref_service) {
       ^{ return [ABAddressBook sharedAddressBook]; });
   UMA_HISTOGRAM_BOOLEAN("Autofill.AddressBookAvailable", addressBook != nil);
 
+  if (!g_accessed_address_book) {
+    // The amount of time that the access takes gives a good indication as to
+    // whether the user was shown a prompt.
+    UMA_HISTOGRAM_TIMES("Autofill.AddressBook.AccessTime",
+                        base::Time::Now() - start_time);
+  }
+
   if (first_access) {
     UMA_HISTOGRAM_BOOLEAN("Autofill.AddressBookAvailableOnFirstAttempt",
                           addressBook != nil);
@@ -169,8 +178,11 @@ void AuxiliaryProfilesImpl::GetAddressBookMeCard(const std::string& app_locale,
   ABAddressBook* addressBook = GetAddressBook(pref_service);
 
   ABPerson* me = [addressBook me];
-  if (!me)
+  if (!me) {
+    UMA_HISTOGRAM_BOOLEAN("Autofill.AddressBook.ContainedUsefulInformation",

[Ilya Sherman, 2015/05/14 21:46:28]

For parallelism with existing histograms, please use MacAddressBook rather than
AddressBook (applies throughout)

[erikchen, 2015/05/15 21:04:50]

Done.

+                          false);
     return;
+  }
 
   ABMultiValue* addresses = [me valueForProperty:kABAddressProperty];
 
@@ -182,6 +194,10 @@ void AuxiliaryProfilesImpl::GetAddressBookMeCard(const std::string& app_locale,
   const size_t kNumHexDigits = 16;
   const size_t kMaxAddressCount = pow(kNumHexDigits, kNumAddressGUIDChars);
   NSUInteger count = MIN([addresses count], kMaxAddressCount);
+
+  UMA_HISTOGRAM_BOOLEAN("Autofill.AddressBook.ContainedUsefulInformation",

[Ilya Sherman, 2015/05/14 21:46:28]

I'd prefer not to repeat the string constant, to avoid the chance of typos. 
Please either define a wrapper function or at least a string constant.

[erikchen, 2015/05/15 21:04:50]

Done.

+                        count != 0);
+
   for (NSUInteger i = 0; i < count; i++) {
     NSDictionary* address = [addresses valueAtIndex:i];
     NSString* addressLabelRaw = [addresses labelAtIndex:i];