[Extensions] Parse schema string directly into a v8 object

extensions/renderer/v8_schema_registry.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/v8_schema_registry.h"
 
 #include <stddef.h>
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/values.h"
 #include "content/public/child/v8_value_converter.h"
 #include "extensions/common/extension_api.h"
 #include "extensions/renderer/object_backed_native_handler.h"
 #include "extensions/renderer/script_context.h"
+#include "extensions/renderer/static_v8_external_one_byte_string_resource.h"
 #include "extensions/renderer/v8_helpers.h"
 
 using content::V8ValueConverter;
 
 namespace extensions {
 
 namespace {
 
 // Recursively freezes every v8 object on |object|.
 void DeepFreeze(const v8::Local<v8::Object>& object,
@@ skipping 95 matching lines @@
     }
   }
 
   // Slow path: Need to build schema first.
 
   v8::Isolate* isolate = v8::Isolate::GetCurrent();
   v8::EscapableHandleScope handle_scope(isolate);
   v8::Local<v8::Context> context = GetOrCreateContext(isolate);
   v8::Context::Scope context_scope(context);
 
-  const base::DictionaryValue* schema =
-      ExtensionAPI::GetSharedInstance()->GetSchema(api);
-  CHECK(schema) << api;
-  std::unique_ptr<V8ValueConverter> v8_value_converter(
-      V8ValueConverter::create());
-  v8::Local<v8::Value> value = v8_value_converter->ToV8Value(schema, context);
-  CHECK(!value.IsEmpty());
+  base::StringPiece schema_string =
+      ExtensionAPI::GetSharedInstance()->GetSchemaStringPiece(api);
+  CHECK(!schema_string.empty());
+  v8::MaybeLocal<v8::String> v8_maybe_string =
+      v8::String::NewExternal(
+          isolate, new StaticV8ExternalOneByteStringResource(schema_string));
+  v8::Local<v8::String> v8_schema_string;
+  CHECK(v8_maybe_string.ToLocal(&v8_schema_string));
 
-  v8::Local<v8::Object> v8_schema(v8::Local<v8::Object>::Cast(value));
-  DeepFreeze(v8_schema, context);
-  schema_cache_->Set(api, v8_schema);
+  v8::MaybeLocal<v8::Value> v8_maybe_schema_value =
+      v8::JSON::Parse(context, v8_schema_string);
+  v8::Local<v8::Value> v8_schema_value;
+  CHECK(v8_maybe_schema_value.ToLocal(&v8_schema_value));
+  CHECK(v8_schema_value->IsObject());
 
-  return handle_scope.Escape(v8_schema);
+  v8::Local<v8::Object> v8_schema_object(
+      v8::Local<v8::Object>::Cast(v8_schema_value));
+  DeepFreeze(v8_schema_object, context);
+
+  schema_cache_->Set(api, v8_schema_object);
+
+  return handle_scope.Escape(v8_schema_object);
 }
 
 v8::Local<v8::Context> V8SchemaRegistry::GetOrCreateContext(
     v8::Isolate* isolate) {
   // It's ok to create local handles in this function, since this is only called
   // when we have a HandleScope.
   if (!context_holder_) {
     context_holder_.reset(new gin::ContextHolder(isolate));
     context_holder_->SetContext(v8::Context::New(isolate));
     schema_cache_.reset(new SchemaCache(isolate));
     return context_holder_->context();
   }
   return context_holder_->context();
 }
 
 }  // namespace extensions