rewrite_to_chrome_style: Fix assert calling getName() when there's none

tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp

 // Copyright 2015 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.
 //
 // Changes Blink-style names to Chrome-style names. Currently transforms:
 //   fields:
 //     int m_operationCount => int operation_count_
 //   variables (including parameters):
 //     int mySuperVariable => int my_super_variable
 //   constants:
@@ skipping 41 matching lines @@
 AST_MATCHER(clang::FunctionDecl, isOverloadedOperator) {
   return Node.isOverloadedOperator();
 }
 
 const char kBlinkFieldPrefix[] = "m_";
 const char kBlinkStaticMemberPrefix[] = "s_";
 
 bool GetNameForDecl(const clang::FunctionDecl& decl,
                     const clang::ASTContext& context,
                     std::string& name) {
-  name = decl.getNameAsString();
+  StringRef original_name = decl.getName();
 
   if (const auto* method = clang::dyn_cast<const clang::CXXMethodDecl>(&decl)) {
     if (!method->isStatic()) {
       // Some methods shouldn't be renamed because reasons.
       static const char* kBlacklist[] = {"begin", "end", "rbegin", "rend",
                                          "trace"};
       for (const auto& b : kBlacklist) {
-        if (name == b)
+        if (original_name == b)
           return false;
       }
     }
   }
 
+  name = original_name.str();
   name[0] = clang::toUppercase(name[0]);
   return true;
 }
 
 // Helper to convert from a camelCaseName to camel_case_name. It uses some
 // heuristics to try to handle acronyms in camel case names correctly.
 std::string CamelCaseToUnderscoreCase(StringRef input) {
   std::string output;
   bool needs_underscore = false;
   bool was_lowercase = false;
@@ skipping 151 matching lines @@
 template <typename DeclNode, typename TargetNode>
 class RewriterBase : public MatchFinder::MatchCallback {
  public:
   explicit RewriterBase(Replacements* replacements)
       : replacements_(replacements) {}
 
   void run(const MatchFinder::MatchResult& result) override {
     std::string new_name;
     const DeclNode* decl = result.Nodes.getNodeAs<DeclNode>("decl");
     clang::ASTContext* context = result.Context;
+    // If false, there's no name to be renamed.
+    if (!decl->getIdentifier())
+      return;
+    // If false, the name was not suitable for renaming.
     if (!GetNameForDecl(*decl, *context, new_name))
       return;
     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;
@@ skipping 318 matching lines @@
   for (const auto& r : replacements) {
     std::string replacement_text = r.getReplacementText().str();
     std::replace(replacement_text.begin(), replacement_text.end(), '\n', '\0');
     llvm::outs() << "r:::" << r.getFilePath() << ":::" << r.getOffset()
                  << ":::" << r.getLength() << ":::" << replacement_text << "\n";
   }
   llvm::outs() << "==== END EDITS ====\n";
 
   return 0;
 }