Expose distiller functions to JavaScript

components/dom_distiller/content/renderer/distiller_native_javascript.cc

+// 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.
+
+#include "components/dom_distiller/content/renderer/distiller_native_javascript.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/dom_distiller/content/common/distiller_javascript_service.mojom.h"
+#include "content/public/common/service_registry.h"
+#include "content/public/renderer/render_frame.h"
+#include "gin/arguments.h"
+#include "gin/function_template.h"
+#include "third_party/WebKit/public/web/WebKit.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
+#include "v8/include/v8.h"
+
+using blink::WebLocalFrame;
+
+namespace dom_distiller {
+
+DistillerNativeJavaScript::DistillerNativeJavaScript(
+    content::RenderFrame* render_frame)
+    : render_frame_(render_frame) {}
+
+DistillerNativeJavaScript::~DistillerNativeJavaScript() {}
+
+void DistillerNativeJavaScript::AddJavaScriptObjectToFrame(
+    v8::Local<v8::Context> context) {
+  v8::Isolate* isolate = blink::mainThreadIsolate();
+  v8::HandleScope handle_scope(isolate);
+  if (context.IsEmpty())
+    return;
+
+  v8::Context::Scope context_scope(context);
+
+  v8::Local<v8::Object> distiller_obj =
+      GetOrCreateDistillerObject(isolate, context->Global());
+
+  distiller_obj->Set(
+      gin::StringToSymbol(isolate, "echo"),
+      gin::CreateFunctionTemplate(
+          isolate, base::Bind(&DistillerNativeJavaScript::DistillerEcho,
+                              base::Unretained(this)))
+          ->GetFunction());
+}
+
+std::string DistillerNativeJavaScript::DistillerEcho(
+    const std::string& message) {
+  if (!distiller_js_service_) {
+    render_frame_->GetServiceRegistry()->ConnectToRemoteService(
+        mojo::GetProxy(&distiller_js_service_));
+  }
+  // TODO(mdjones): It is possible and beneficial to have information
+  // returned from the browser process with these calls. The problem
+  // is waiting blocks this process.
+  distiller_js_service_->HandleDistillerEchoCall(message);
+
+  return message;
+}
+
+v8::Local<v8::Object> GetOrCreateDistillerObject(v8::Isolate* isolate,
+                                                 v8::Local<v8::Object> global) {
+  v8::Local<v8::Object> distiller_obj;
+  v8::Local<v8::Value> distiller_value =
+      global->Get(gin::StringToV8(isolate, "distiller"));
+  if (distiller_value.IsEmpty() || !distiller_value->IsObject()) {
+    distiller_obj = v8::Object::New(isolate);
+    global->Set(gin::StringToSymbol(isolate, "distiller"), distiller_obj);
+  } else {
+    distiller_obj = v8::Local<v8::Object>::Cast(distiller_value);
+  }
+  return distiller_obj;
+}
+
+}  // namespace dom_distiller