[Extensions Bindings] Add a bridge to use current custom bindings

extensions/renderer/api_binding_bridge.cc

Index: extensions/renderer/api_binding_bridge.cc
diff --git a/extensions/renderer/api_binding_bridge.cc b/extensions/renderer/api_binding_bridge.cc
new file mode 100644
index 0000000000000000000000000000000000000000..264805684134ede7f976a4a805a4f57a8c63c442
--- /dev/null
+++ b/extensions/renderer/api_binding_bridge.cc
@@ -0,0 +1,103 @@
+// Copyright 2016 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/api_binding_bridge.h"
+
+#include "gin/converter.h"
+#include "gin/object_template_builder.h"
+
+namespace extensions {
+
+namespace {
+
+const char kApiObjectKey[] = "extensions::bridge::api_object";
+const char kHookObjectKey[] = "extensions::bridge::hook_object";
+
+v8::Local<v8::Private> GetPrivatePropertyName(v8::Isolate* isolate,
+                                              const char* key) {
+  return v8::Private::ForApi(isolate, gin::StringToSymbol(isolate, key));
+}
+
+}  // namespace
+
+gin::WrapperInfo APIBindingBridge::kWrapperInfo = {gin::kEmbedderNativeGin};
+
+APIBindingBridge::APIBindingBridge(v8::Local<v8::Context> context,
+                                   v8::Local<v8::Value> api_object,
+                                   v8::Local<v8::Value> js_hook_interface,
+                                   const std::string& extension_id,
+                                   const std::string& context_type,
+                                   const binding::RunJSFunction& run_js)
+    : extension_id_(extension_id),
+      context_type_(context_type),
+      run_js_(run_js) {
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::Local<v8::Object> wrapper = GetWrapper(isolate);
+  v8::Maybe<bool> result = wrapper->SetPrivate(
+      context, GetPrivatePropertyName(isolate, kApiObjectKey), api_object);
+  if (!result.IsJust() || !result.FromJust()) {
+    NOTREACHED();
+    return;
+  }
+  result = wrapper->SetPrivate(context,
+                               GetPrivatePropertyName(isolate, kHookObjectKey),
+                               js_hook_interface);
+  DCHECK(result.IsJust() && result.FromJust());
+}
+
+APIBindingBridge::~APIBindingBridge() {}
+
+gin::ObjectTemplateBuilder APIBindingBridge::GetObjectTemplateBuilder(
+    v8::Isolate* isolate) {
+  return Wrappable<APIBindingBridge>::GetObjectTemplateBuilder(isolate)
+      .SetMethod("registerCustomHook", &APIBindingBridge::RegisterCustomHook);
+}
+
+void APIBindingBridge::RegisterCustomHook(v8::Isolate* isolate,
+                                          v8::Local<v8::Function> function) {
+  // The object and arguments here are meant to match those passed to the hook
+  // functions in binding.js.
+  v8::Local<v8::Context> context = isolate->GetCurrentContext();
+  v8::Local<v8::Object> hook_object = v8::Object::New(isolate);
+  v8::Local<v8::Object> wrapper = GetWrapper(isolate);
+  v8::Local<v8::Value> hook_interface;

[jbroman, 2016/12/20 20:51:34]

The naming is a little funny here, with kHookObjectKey corresponding to
hook_interface, rather than hook_object.

[Devlin, 2016/12/20 22:20:19]

s/kHookObjectKey/kHookInterfaceKey

+  if (!wrapper
+           ->GetPrivate(context,
+                        GetPrivatePropertyName(isolate, kHookObjectKey))
+           .ToLocal(&hook_interface)) {
+    return;

[jbroman, 2016/12/20 20:51:34]

nit: It'd be pretty surprising for these private properties to go away. I'd at
least NOTREACHED if that happens, or possibly just use ToLocalChecked.

[Devlin, 2016/12/20 22:20:19]

ToLocalChecked()'ing.

+  }
+  v8::Maybe<bool> result = hook_object->CreateDataProperty(
+      context, gin::StringToSymbol(isolate, "apiFunctions"), hook_interface);
+  if (!result.IsJust() || !result.FromJust())
+    return;
+
+  v8::Local<v8::Value> api_object;
+  if (!wrapper
+           ->GetPrivate(context, GetPrivatePropertyName(isolate, kApiObjectKey))
+           .ToLocal(&api_object)) {
+    return;
+  }
+  result = hook_object->CreateDataProperty(
+      context, gin::StringToSymbol(isolate, "compiledApi"), api_object);
+  if (!result.IsJust() || !result.FromJust())
+    return;
+
+  // TODO(devlin): The binding.js version of these hooks also has a 'schema'
+  // property. I wonder if we can factor that out? If not, we'll need to add it
+  // here.
+
+  result = hook_object->SetPrototype(context, v8::Null(isolate));
+  if (!result.IsJust() || !result.FromJust())
+    return;
+
+  v8::Local<v8::String> extension_id =
+      gin::StringToSymbol(isolate, extension_id_);
+  v8::Local<v8::String> context_type =
+      gin::StringToSymbol(isolate, context_type_);
+  v8::Local<v8::Value> args[] = {hook_object, extension_id, context_type};
+  run_js_.Run(function, context, arraysize(args), args);
+}
+
+}  // namespace extensions