rewrite_to_chrome_style: skip nodes expanded from macros

Since the tool wasn't using the "spelling" location, replacements would
be emitted using source locations into an unnamed input buffer. As a
result, the emitted replacements would never apply since the file name
would never match.

However, it ends up still being included in the symbol dump for the
rebase tool. Since these identifiers aren't being renamed, just skip
processing anything inside a macro.

BUG=581902

Review URL: https://codereview.chromium.org/1641703003

Cr-Commit-Position: refs/heads/master@{#372203}

tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp

@@ -241,20 +241,21 @@ class RewriterBase : public MatchFinder::MatchCallback {
       : replacements_(replacements) {}
 
   void run(const MatchFinder::MatchResult& result) override {
-    std::string name;
+    std::string new_name;
     const DeclNode* decl = result.Nodes.getNodeAs<DeclNode>("decl");
     clang::ASTContext* context = result.Context;
-    if (!GetNameForDecl(*decl, *context, name))
+    if (!GetNameForDecl(*decl, *context, new_name))
       return;
-    auto r = replacements_->emplace(
-        *result.SourceManager, TargetNodeTraits<TargetNode>::GetRange(
-                                   *result.Nodes.getNodeAs<TargetNode>(
-                                       TargetNodeTraits<TargetNode>::kName)),
-        name);
-    auto from = decl->getNameAsString();
-    auto to = r.first->getReplacementText().str();
-    if (from != to)
-      replacement_names_.emplace(std::move(from), std::move(to));
+    llvm::StringRef old_name = decl->getName();
+    if (old_name == new_name)
+      return;
+    clang::CharSourceRange range = TargetNodeTraits<TargetNode>::GetRange(
+        *result.Nodes.getNodeAs<TargetNode>(
+            TargetNodeTraits<TargetNode>::kName));
+    if (range.getBegin().isMacroID() || range.getEnd().isMacroID())
+      return;
+    replacements_->emplace(*result.SourceManager, range, new_name);
+    replacement_names_.emplace(old_name.str(), std::move(new_name));
   }
 
   const std::unordered_map<std::string, std::string>& replacement_names()