Add webusb notification UI code

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 669b84e44ee92fa57fc7e7a1b1b72c036fd838b0..f911eb11959af2079c85652f9163b95ec7d52242 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -234,6 +234,10 @@
 #include "ui/aura/env.h"
 #endif  // defined(USE_AURA)
 
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+#include "components/webusb/webusb_detector.h"
+#endif
+
 using content::BrowserThread;
 
 namespace {
@@ -1150,6 +1154,10 @@ void ChromeBrowserMainParts::PostBrowserStart() {
       base::TimeDelta::FromMinutes(1));
 #endif  // defined(ENABLE_WEBRTC)
 
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+  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.