Reland reverted patch once the webkit tests that were failing are

chrome/browser/notifications/notification_common.cc

 // Copyright 2016 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/notifications/notification_common.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/chrome_pages.h"
+#include "chrome/browser/ui/exclusive_access/exclusive_access_context.h"
+#include "chrome/browser/ui/exclusive_access/exclusive_access_manager.h"
 #include "chrome/browser/ui/scoped_tabbed_browser_displayer.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/public/browser/browser_context.h"
+#include "ui/message_center/notifier_settings.h"
+
+namespace features {
+
+const base::Feature kAllowFullscreenWebNotificationsFeature{
+    "FSNotificationsWeb", base::FEATURE_ENABLED_BY_DEFAULT};
+
+}  // namespace features
 
 // static
 void NotificationCommon::OpenNotificationSettings(
     content::BrowserContext* browser_context) {
 #if defined(OS_ANDROID)
   // Android settings are opened directly from Java
   NOTIMPLEMENTED();
 #else
   Profile* profile = Profile::FromBrowserContext(browser_context);
   DCHECK(profile);
 
   if (switches::SettingsWindowEnabled()) {
     chrome::ShowContentSettingsExceptionsInWindow(
         profile, CONTENT_SETTINGS_TYPE_NOTIFICATIONS);
   } else {
     chrome::ScopedTabbedBrowserDisplayer browser_displayer(profile);
     chrome::ShowContentSettingsExceptions(browser_displayer.browser(),
                                           CONTENT_SETTINGS_TYPE_NOTIFICATIONS);
   }
 #endif  // defined(OS_ANDROID)
 }
+
+// static
+bool NotificationCommon::ShouldDisplayOnFullScreen(Profile* profile,
+                                                   const GURL& origin) {
+#if defined(OS_ANDROID)
+  NOTIMPLEMENTED();
+  return false;
+#endif  // defined(OS_ANDROID)
+
+  // Check to see if this notification comes from a webpage that is displaying
+  // fullscreen content.
+  for (auto* browser : *BrowserList::GetInstance()) {
+    // Only consider the browsers for the profile that created the notification
+    if (browser->profile() != profile)
+      continue;
+
+    const content::WebContents* active_contents =
+        browser->tab_strip_model()->GetActiveWebContents();
+    if (!active_contents)
+      continue;
+
+    // Check to see if
+    //  (a) the active tab in the browser shares its origin with the
+    //      notification.
+    //  (b) the browser is fullscreen
+    //  (c) the browser has focus.
+    if (active_contents->GetURL().GetOrigin() == origin &&
+        browser->exclusive_access_manager()->context()->IsFullscreen() &&
+        browser->window()->IsActive()) {
+      bool enabled = base::FeatureList::IsEnabled(
+          features::kAllowFullscreenWebNotificationsFeature);
+      if (enabled) {
+        UMA_HISTOGRAM_ENUMERATION("Notifications.Display_Fullscreen.Shown",
+                                  message_center::NotifierId::WEB_PAGE,
+                                  message_center::NotifierId::SIZE);
+      } else {
+        UMA_HISTOGRAM_ENUMERATION("Notifications.Display_Fullscreen.Suppressed",
+                                  message_center::NotifierId::WEB_PAGE,
+                                  message_center::NotifierId::SIZE);
+      }
+      return enabled;
+    }
+  }
+  return false;
+}