Add variable for --testing-fixed-https?-port switches on iOS.

ios/chrome/browser/chrome_switches.cc

Index: ios/chrome/browser/chrome_switches.cc
diff --git a/ios/chrome/browser/chrome_switches.cc b/ios/chrome/browser/chrome_switches.cc
index e2934c1968e23d83b562ab82b4eb0e57793e27b7..c069fd53176763c3860c6eb71584a729c1224bd6 100644
--- a/ios/chrome/browser/chrome_switches.cc
+++ b/ios/chrome/browser/chrome_switches.cc
@@ -94,4 +94,8 @@ const char kUserAgent[] = "user-agent";
 // These mappings only apply to the host resolver.
 const char kIOSHostResolverRules[] = "host-resolver-rules";
 
+// Allows for forcing socket connections to http/https to use fixed ports.
+const char kIOSTestingFixedHttpPort[] = "testing-fixed-http-port";
+const char kIOSTestingFixedHttpsPort[] = "testing-fixed-https-port";
+
 }  // namespace switches