Add webusb notification UI code

chrome/browser/chrome_webusb_browser_client.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 "chrome/browser/chrome_webusb_browser_client.h"
+
+#include "base/command_line.h"
+#include "chrome/browser/net/referrer.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/host_desktop.h"
+#include "chrome/common/chrome_switches.h"
+#include "ui/base/page_transition_types.h"
+#include "ui/base/window_open_disposition.h"
+#include "url/gurl.h"
+
+ChromeWebUsbBrowserClient::ChromeWebUsbBrowserClient() {}
+
+ChromeWebUsbBrowserClient::~ChromeWebUsbBrowserClient() {}
+
+void ChromeWebUsbBrowserClient::OpenURL(Profile* profile, const GURL& url) {
+  Browser* browser =
+      chrome::FindBrowserWithProfile(profile, chrome::HOST_DESKTOP_TYPE_NATIVE);

[Reilly Grant (use Gerrit), 2015/08/18 18:30:02]

I think we can use ProfileManager::GetActiveProfile() to find the active user
profile. This means that we don't need to pass a profile all the way through the
detector service.

As a bonus, this means that the detector service doesn't need to be a
KeyedService. There really should only be one instance for the whole browser
anyways since we don't want to display multiple notifications. The way that you
are currently adding notifications to the message center means that they are
visible to all users so right now you will get one notification per profile
which is not what we want.

[juncai, 2015/08/20 15:56:32]

Done.

+  content::OpenURLParams params(url, content::Referrer(), NEW_FOREGROUND_TAB,
+                                ui::PAGE_TRANSITION_AUTO_TOPLEVEL, true);
+  browser->OpenURL(params);
+}
+
+bool ChromeWebUsbBrowserClient::WebUsbNotificationEnabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableWebUsbNotification);
+}