Make ModuleSystem have a const view of ResourceBundleSourceMap.

extensions/renderer/resource_bundle_source_map.cc

 // Copyright 2014 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 "extensions/renderer/resource_bundle_source_map.h"
 
 #include "base/logging.h"
+#include "base/strings/string_piece.h"
+#include "extensions/renderer/static_v8_external_one_byte_string_resource.h"
 #include "ui/base/resource/resource_bundle.h"
 
 namespace extensions {
 
+namespace {
+
+v8::Local<v8::String> ConvertString(v8::Isolate* isolate,
+                                    const base::StringPiece& string) {
+  // v8 takes ownership of the StaticV8ExternalOneByteStringResource (see
+  // v8::String::NewExternal()).
+  return v8::String::NewExternal(
+      isolate, new StaticV8ExternalOneByteStringResource(string));
+}
+
+}  // namespace
+
 ResourceBundleSourceMap::ResourceBundleSourceMap(
     const ui::ResourceBundle* resource_bundle)
     : resource_bundle_(resource_bundle) {
 }
 
 ResourceBundleSourceMap::~ResourceBundleSourceMap() {
 }
 
 void ResourceBundleSourceMap::RegisterSource(const std::string& name,
                                              int resource_id) {
   resource_id_map_[name] = resource_id;
 }
 
 v8::Local<v8::Value> ResourceBundleSourceMap::GetSource(
     v8::Isolate* isolate,
-    const std::string& name) {
+    const std::string& name) const {
   if (!Contains(name)) {

[Devlin, 2016/04/12 17:01:25]

nit: another double-lookup.

[lazyboy, 2016/04/12 17:29:28]

Done.

     NOTREACHED() << "No module is registered with name \"" << name << "\"";
     return v8::Undefined(isolate);
   }
+  int resource_id = resource_id_map_.find(name)->second;
   base::StringPiece resource =
-      resource_bundle_->GetRawDataResource(resource_id_map_[name]);
+      resource_bundle_->GetRawDataResource(resource_id);
   if (resource.empty()) {
     NOTREACHED()
         << "Module resource registered as \"" << name << "\" not found";
     return v8::Undefined(isolate);
   }
   return ConvertString(isolate, resource);
 }
 
-bool ResourceBundleSourceMap::Contains(const std::string& name) {
+bool ResourceBundleSourceMap::Contains(const std::string& name) const {
   return !!resource_id_map_.count(name);
 }
 
-v8::Local<v8::String> ResourceBundleSourceMap::ConvertString(
-    v8::Isolate* isolate,
-    const base::StringPiece& string) {
-  // v8 takes ownership of the StaticV8ExternalOneByteStringResource (see
-  // v8::String::NewExternal()).
-  return v8::String::NewExternal(
-      isolate, new StaticV8ExternalOneByteStringResource(string));
-}
-
 }  // namespace extensions