Add UMA histograms for WebUSB.

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 <utility>
 
 #include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/net/referrer.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "chrome/browser/ui/scoped_tabbed_browser_displayer.h"
 #include "chrome/grit/generated_resources.h"
 #include "chrome/grit/theme_resources.h"
 #include "content/public/common/origin_util.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/page_transition_types.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/window_open_disposition.h"
 #include "ui/gfx/image/image.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/notification.h"
 #include "ui/message_center/notification_delegate.h"
 #include "url/gurl.h"
 
 namespace {
 
 const char kWebUsbDetectorNotificationID[] = "webusb.detector";
 
+enum WebUsbNotificationClosed {

[asargent_no_longer_on_chrome, 2016/01/21 18:54:15]

nit: We typically include a comment above enums used in histograms warning
people not to remove/reorder/renumber items in them; it would be good to do so
here. (You can search around the extensions system for similar comments and crib
their form or whatever)

(same comment applies to new enums in other files in the CL)

+  // The notification was dismissed but not by the user (either automatically
+  // or because the device was unplugged).
+  WEBUSB_NOTIFICATION_CLOSED,
+  // The user closed the notification.
+  WEBUSB_NOTIFICATION_CLOSED_BY_USER,
+  // The user clicked on the notification.
+  WEBUSB_NOTIFICATION_CLOSED_CLICKED,
+  // Maximum value for the enum.
+  WEBUSB_NOTIFICATION_CLOSED_MAX
+};
+
+void RecordNotificationClosure(WebUsbNotificationClosed disposition) {
+  UMA_HISTOGRAM_ENUMERATION("WebUsb.NotificationClosed", disposition,
+                            WEBUSB_NOTIFICATION_CLOSED_MAX);
+}
+
 Browser* GetBrowser() {
   chrome::ScopedTabbedBrowserDisplayer browser_displayer(
       ProfileManager::GetActiveUserProfile(), chrome::GetActiveDesktop());
   DCHECK(browser_displayer.browser());
   return browser_displayer.browser();
 }
 
 void OpenURL(const GURL& url) {
   GetBrowser()->OpenURL(
       content::OpenURLParams(url, content::Referrer(), NEW_FOREGROUND_TAB,
                              ui::PAGE_TRANSITION_AUTO_TOPLEVEL, true));
 }
 
 // Delegate for webusb notification
 class WebUsbNotificationDelegate : public message_center::NotificationDelegate {
  public:
   WebUsbNotificationDelegate(const GURL& landing_page,
                              const std::string& notification_id)
       : landing_page_(landing_page), notification_id_(notification_id) {}
 
   void Click() override {
+    clicked_ = true;
     OpenURL(landing_page_);
     message_center::MessageCenter::Get()->RemoveNotification(
         notification_id_, false /* by_user */);
   }
 
+  void Close(bool by_user) override {
+    if (clicked_)
+      RecordNotificationClosure(WEBUSB_NOTIFICATION_CLOSED_CLICKED);
+    else if (by_user)
+      RecordNotificationClosure(WEBUSB_NOTIFICATION_CLOSED_BY_USER);
+    else
+      RecordNotificationClosure(WEBUSB_NOTIFICATION_CLOSED);
+  }
+
  private:
   ~WebUsbNotificationDelegate() override = default;
 
   GURL landing_page_;
   std::string notification_id_;
+  bool clicked_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WebUsbNotificationDelegate);
 };
 
 }  // namespace
 
 ChromeWebUsbBrowserClient::ChromeWebUsbBrowserClient() {}
 
 ChromeWebUsbBrowserClient::~ChromeWebUsbBrowserClient() {}
 
@@ skipping 29 matching lines @@
 }
 
 void ChromeWebUsbBrowserClient::OnDeviceRemoved(
     const std::string& notification_id) {
   message_center::MessageCenter* message_center =
       message_center::MessageCenter::Get();
   if (message_center->FindVisibleNotificationById(notification_id)) {
     message_center->RemoveNotification(notification_id, false /* by_user */);
   }
 }