mac: Expose keychain access frequency to Telemetry.

crypto/mock_apple_keychain.cc

Index: crypto/mock_apple_keychain.cc
diff --git a/crypto/mock_apple_keychain.cc b/crypto/mock_apple_keychain.cc
index 65d3a07961c182c61516fd0022b962b562b100a3..da34d156fec773747af32938c495d35ecb041afb 100644
--- a/crypto/mock_apple_keychain.cc
+++ b/crypto/mock_apple_keychain.cc
@@ -22,6 +22,7 @@ OSStatus MockAppleKeychain::FindGenericPassword(
   // 4.6ms with a SSD, 3 GHz Intel Xeon. On a slower processor with a HDD, this
   // probably takes 4x as long.
   base::SpinCpuMicroseconds(18400);
+  base::EmitAccessKeychainHistogram();
 
   // When simulating |noErr|, return canned |passwordData| and
   // |passwordLength|.  Otherwise, just return given code.
@@ -58,6 +59,7 @@ OSStatus MockAppleKeychain::AddGenericPassword(
   // 6ms with a SSD, 3 GHz Intel Xeon. On a slower processor with a HDD, this
   // probably takes 4x as long.
   base::SpinCpuMicroseconds(24000);
+  base::EmitAccessKeychainHistogram();
 
   called_add_generic_ = true;