Fix #includes in components/proximity_auth/cryptauth.

components/proximity_auth/switches.cc

Index: components/proximity_auth/switches.cc
diff --git a/components/proximity_auth/switches.cc b/components/proximity_auth/switches.cc
index 15b9e9bca70c353d4ac900dca74560f6a3d7e136..38c5e9e6e9097d764e6dc1acc3e22db11d0450c1 100644
--- a/components/proximity_auth/switches.cc
+++ b/components/proximity_auth/switches.cc
@@ -7,10 +7,6 @@
 namespace proximity_auth {
 namespace switches {
 
-// Overrides the default URL for Google APIs (https://www.googleapis.com) used
-// by CryptAuth.
-const char kCryptAuthHTTPHost[] = "cryptauth-http-host";
-
 // Enables discovery of the phone over Bluetooth Low Energy.
 const char kEnableBluetoothLowEnergyDiscovery[] =
     "enable-proximity-auth-bluetooth-low-energy-discovery";