Support rewriting |to##macroArg()| into |To##macroArg()|.

tools/clang/rewrite_to_chrome_style/tests/macros-original.cc

Index: tools/clang/rewrite_to_chrome_style/tests/macros-original.cc
diff --git a/tools/clang/rewrite_to_chrome_style/tests/macros-original.cc b/tools/clang/rewrite_to_chrome_style/tests/macros-original.cc
index ab684841ea60ae4f36a8f4d39e26c174e004dc31..4b766501dd1f2ce65a2b4f71053de350869e2bed 100644
--- a/tools/clang/rewrite_to_chrome_style/tests/macros-original.cc
+++ b/tools/clang/rewrite_to_chrome_style/tests/macros-original.cc
@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Identifiers in macros should never be rewritten, as the risk of things
-// breaking is extremely high.
-
 #define DEFINE_TYPE_CASTS(thisType, argumentType, argumentName, predicate) \
   inline thisType* to##thisType(argumentType* argumentName) {              \
     if (!predicate)                                                        \
@@ -26,8 +23,6 @@ DEFINE_TYPE_CASTS(Derived, Base, object, true);
 
 void F() {
   Base* basePtr = new Derived;
-  // 'toDerived' should not be renamed, since the definition lives inside
-  // a macro invocation.
   Derived* derivedPtr = toDerived(basePtr);
   long long asInt = toInt(basePtr);
   // 'derivedPtr' should be renamed: it's a reference to a declaration defined
@@ -50,4 +45,23 @@ struct WithMacro : public WithMacroP {
   CALL_METHOD_FROM_MACRO();
 };
 
+#define DEFINE_WITH_TOKEN_CONCATENATION2(arg1, arg2) \
+  void arg1##arg2() {}
+// We definitely don't want to rewrite |arg1| on the previous line into
+// either |Arg1| or |Frg1| or |Brg1| or |Foo| or |Baz|.
+
+// We might or might not want to rewrite |foo|->|Foo| and |baz|->|Baz| below.
+// The test below just spells out the current behavior of the tool (which one
+// can argue is accidental).
+DEFINE_WITH_TOKEN_CONCATENATION2(foo, Bar1)
+DEFINE_WITH_TOKEN_CONCATENATION2(baz, Bar2)
+
+void tokenConcatenationTest2() {
+  // We might or might not want to rewrite |foo|->|Foo| and |baz|->|Baz| below.
+  // The test below just spells out the current behavior of the tool (which one
+  // can argue is accidental).
+  fooBar1();
+  bazBar2();
+}
+
 }  // namespace blink