mac: Expose keychain access frequency to Telemetry.

crypto/mock_apple_keychain.h

Index: crypto/mock_apple_keychain.h
diff --git a/crypto/mock_apple_keychain.h b/crypto/mock_apple_keychain.h
index 28c77b82c7cc0703718788b15b1172cd5926cbce..3948d489755a3049a268772763648fe5d3cf9994 100644
--- a/crypto/mock_apple_keychain.h
+++ b/crypto/mock_apple_keychain.h
@@ -51,6 +51,9 @@ class CRYPTO_EXPORT MockAppleKeychain : public AppleKeychain {
                               const void* passwordData,
                               SecKeychainItemRef* itemRef) const override;
 
+  // Returns the password that OSCrypt uses to generate its encryption key.
+  std::string GetEncryptionPassword() const;
+
 #if !defined(OS_IOS)
   OSStatus ItemCopyAttributesAndData(SecKeychainItemRef itemRef,
                                      SecKeychainAttributeInfo* info,