clang plugin: Remove follow-macro-expansion toggle

tools/clang/plugins/FindBadConstructsAction.cpp

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "FindBadConstructsAction.h"
 
 #include "clang/AST/ASTConsumer.h"
 #include "clang/Frontend/FrontendPluginRegistry.h"
 
 #include "FindBadConstructsConsumer.h"
@@ skipping 40 matching lines @@
       options_.enforce_in_pdf = true;
     } else if (args[i] == "enforce-in-thirdparty-webkit") {
       options_.enforce_in_thirdparty_webkit = true;
     } else if (args[i] == "check-enum-last-value") {
       // TODO(tsepez): Enable this by default once http://crbug.com/356815
       // and http://crbug.com/356816 are fixed.
       options_.check_enum_last_value = true;
     } else if (args[i] == "check-templates") {
       options_.check_templates = true;
     } else if (args[i] == "follow-macro-expansion") {
-      options_.follow_macro_expansion = true;
+      // TODO(thakis): This is now always on. Remove support for this flag once
+      // the build no longer passes it in.
     } else if (args[i] == "no-realpath") {
       options_.no_realpath = true;
     } else if (args[i] == "check-ipc") {
       options_.check_ipc = true;
     } else if (args[i] == "check-auto-raw-pointer") {
       options_.check_auto_raw_pointer = true;
     } else if (args[i] == "check-implicit-copy-ctors") {
       // This is deprecated and will be removed once the flag is not used.
     } else {
       parsed = false;
       llvm::errs() << "Unknown clang plugin argument: " << args[i] << "\n";
     }
   }
 
   return parsed;
 }
 
 }  // namespace chrome_checker
 
 static FrontendPluginRegistry::Add<chrome_checker::FindBadConstructsAction> X(
     "find-bad-constructs",
     "Finds bad C++ constructs");