Add webusb notification UI code

chrome/browser/chrome_browser_main.cc

 // Copyright (c) 2012 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_browser_main.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 217 matching lines @@
 #endif  // defined(ENABLE_RLZ)
 
 #if defined(ENABLE_WEBRTC)
 #include "chrome/browser/media/webrtc_log_util.h"
 #endif  // defined(ENABLE_WEBRTC)
 
 #if defined(USE_AURA)
 #include "ui/aura/env.h"
 #endif  // defined(USE_AURA)
 
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+#include "chrome/browser/chrome_webusb_browser_client.h"
+#include "components/webusb/webusb_detector.h"
+#endif
+
 using content::BrowserThread;
 
 namespace {
 
 // This function provides some ways to test crash and assertion handling
 // behavior of the program.
 void HandleTestParameters(const base::CommandLine& command_line) {
   // This parameter causes a null pointer crash (crash reporter trigger).
   if (command_line.HasSwitch(switches::kBrowserCrashTest)) {
     int* bad_pointer = NULL;
@@ skipping 885 matching lines @@
 #if defined(ENABLE_WEBRTC)
   // Set up a task to delete old WebRTC log files for all profiles. Use a delay
   // to reduce the impact on startup time.
   BrowserThread::PostDelayedTask(
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&WebRtcLogUtil::DeleteOldWebRtcLogFilesForAllProfiles),
       base::TimeDelta::FromMinutes(1));
 #endif  // defined(ENABLE_WEBRTC)
 
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+  scoped_ptr<webusb::WebUsbBrowserClient> webusb_browser_client_ptr(
+      new ChromeWebUsbBrowserClient());
+  if (webusb_browser_client_ptr->WebUsbNotificationEnabled()) {

[Reilly Grant (use Gerrit), 2015/08/21 17:23:02]

Why does this condition only guard the call to Set? Why create a
ChromeWebUsbBrowserClient and WebUsbDetector if the flag isn't enabled?

[juncai, 2015/08/21 20:18:27]

Done.

+    webusb::WebUsbBrowserClient::Set(webusb_browser_client_ptr.release());
+  }
+  webusb::WebUsbDetector::GetInstance();
+#endif
+
   // At this point, StartupBrowserCreator::Start has run creating initial
   // browser windows and tabs, but no progress has been made in loading
   // content as the main message loop hasn't started processing tasks yet.
   // We setup to observe to the initial page load here to defer running
   // task posted via PostAfterStartupTask until its complete.
   AfterStartupTaskUtils::StartMonitoringStartup();
 }
 
 int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::PreMainMessageLoopRunImpl");
@@ skipping 639 matching lines @@
   chromeos::CrosSettings::Shutdown();
 #endif  // defined(OS_CHROMEOS)
 #endif  // defined(OS_ANDROID)
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }