Create chrome://device-emulator and add the ability to get a battery percentage and send an updated…

chrome/browser/ui/webui/chromeos/emulator/device_emulator_message_handler.cc

Index: chrome/browser/ui/webui/chromeos/emulator/device_emulator_message_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/emulator/device_emulator_message_handler.cc b/chrome/browser/ui/webui/chromeos/emulator/device_emulator_message_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e2c534a5b45f45fb008f1c9a15f05085d7747eaf
--- /dev/null
+++ b/chrome/browser/ui/webui/chromeos/emulator/device_emulator_message_handler.cc
@@ -0,0 +1,59 @@
+// 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 "chrome/browser/ui/webui/chromeos/emulator/device_emulator_message_handler.h"
+
+#include <stdlib.h>
+
+#include "base/bind.h"
+#include "base/values.h"
+#include "content/public/browser/web_ui.h"
+
+namespace {
+
+// Define the name of the callback functions that will be used by JavaScript.
+const char kBatteryPercentFunction[] = "requestBatteryInfo";
+const char kUpdateBatteryPercentFunction[] = "updateBatteryInfo";
+const char kUpdatePowerModeFunction[] = "updatePowerSource";
+const char kBatteryPercentFunctionJSCallback[] =
+    "device_emulator.setBatteryInfo";
+
+}  // namespace
+
+DeviceEmulatorMessageHandler::DeviceEmulatorMessageHandler() {
+}
+
+DeviceEmulatorMessageHandler::~DeviceEmulatorMessageHandler() {
+}
+
+void DeviceEmulatorMessageHandler::RegisterMessages() {
+  web_ui()->RegisterMessageCallback(
+      kBatteryPercentFunction,
+      base::Bind(&DeviceEmulatorMessageHandler::HandleRequestBatteryInfo,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      kUpdateBatteryPercentFunction,
+      base::Bind(&DeviceEmulatorMessageHandler::HandleUpdateBatteryInfo,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      kUpdatePowerModeFunction,
+      base::Bind(&DeviceEmulatorMessageHandler::HandleUpdatePowerSource,
+                 base::Unretained(this)));
+}
+
+void DeviceEmulatorMessageHandler::HandleRequestBatteryInfo(
+    const base::ListValue* args) {
+  web_ui()->CallJavascriptFunction(kBatteryPercentFunctionJSCallback,
+                                   base::FundamentalValue(rand() % 101));
+}
+
+void DeviceEmulatorMessageHandler::HandleUpdateBatteryInfo(
+    const base::ListValue* args) {
+  int new_percent = -1;
+  args->GetInteger(0, &new_percent);
+}
+
+void DeviceEmulatorMessageHandler::HandleUpdatePowerSource(
+    const base::ListValue* args) {
+}