rewrite_to_chrome_style: Make const decisions aware of const variables

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 391 matching lines @@
   // We do our best to figure out special cases as we come across them here, for
   // template dependent situations. Some cases in code are only considered
   // instantiation dependent for some template instantiations! Which is
   // terrible! So most importantly we try to match isEvaluatable in those cases.
   switch (expr->getStmtClass()) {
     case clang::Stmt::CXXThisExprClass:
       return false;
     case clang::Stmt::DeclRefExprClass: {
       auto* declref = clang::dyn_cast<clang::DeclRefExpr>(expr);
       auto* decl = declref->getDecl();
-      if (clang::dyn_cast<clang::VarDecl>(decl))
+      if (auto* vardecl = clang::dyn_cast<clang::VarDecl>(decl)) {
+        if (auto* initializer = vardecl->getInit())
+          return CanBeEvaluatedAtCompileTime(initializer, context);
         return false;
+      }
       break;
     }
 
     default:
       break;
   }
 
   // Otherwise, we consider depending on template parameters to not interfere
   // with being const.. with exceptions hopefully covered above.
   return true;
@@ skipping 1084 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;
 }