Very basic change to add a TriggerManager class owned by SafeBrowsingService.

chrome/browser/safe_browsing/safe_browsing_service.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/safe_browsing/safe_browsing_service.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 21 matching lines @@
 #include "chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h"
 #include "chrome/browser/safe_browsing/ui_manager.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/safe_browsing/file_type_policies.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "components/prefs/pref_service.h"
 #include "components/safe_browsing/common/safebrowsing_constants.h"
 #include "components/safe_browsing/common/safebrowsing_switches.h"
+#include "components/safe_browsing/triggers/trigger_manager.h"
 #include "components/safe_browsing_db/database_manager.h"
 #include "components/safe_browsing_db/v4_feature_list.h"
 #include "components/safe_browsing_db/v4_get_hash_protocol_manager.h"
 #include "components/safe_browsing_db/v4_local_database_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/cookie_store_factory.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/resource_request_info.h"
 #include "google_apis/google_api_keys.h"
 #include "net/cookies/cookie_store.h"
@@ skipping 273 matching lines @@
   }
 
   if (base::FeatureList::IsEnabled(
     SafeBrowsingNavigationObserverManager::kDownloadAttribution)) {
     navigation_observer_manager_ = new SafeBrowsingNavigationObserverManager();
   }
 
   services_delegate_->Initialize(v4_enabled_);
   services_delegate_->InitializeCsdService(url_request_context_getter_.get());
 
+  CreateTriggerManager();
+
   // Track profile creation and destruction.
   profiles_registrar_.Add(this, chrome::NOTIFICATION_PROFILE_CREATED,
                           content::NotificationService::AllSources());
   profiles_registrar_.Add(this, chrome::NOTIFICATION_PROFILE_DESTROYED,
                           content::NotificationService::AllSources());
 
   // Register all the delayed analysis to the incident reporting service.
   RegisterAllDelayedAnalysis();
 }
 
@@ skipping 427 matching lines @@
 }
 
 void SafeBrowsingService::RemovePasswordProtectionService(Profile* profile) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(profile);
   auto it = password_protection_service_map_.find(profile);
   if (it != password_protection_service_map_.end())
     password_protection_service_map_.erase(it);
 }
 
+void SafeBrowsingService::CreateTriggerManager() {

[Jialiu Lin, 2017/05/04 15:53:38]

How does TriggerManager tie to profile?   If TriggerManager reacts differently
based on Prefs/Profile, do you want to consider making it a per-profile class.
Since components/safe_browsing/ has no access to Profile class. 

[lpz, 2017/05/04 17:51:53]

Good question. I've been thinking of TriggerManager operating on WebContents
objects for now (eg listening for WebContents being created/destroyed, keeping a
list of active WebContents). So we have 1 TriggerManager mapping to many
WebContents. We can get the profile for each WebContents, right? So we could
make a decision about what triggers to run for each WebContents independently?

I suppose we only really need the prefservice (which is a component) and the
incognito state (from the browsercontext) for each webcontents, so we may not
need the profile itself.

WDYT?

[Jialiu Lin, 2017/05/04 18:29:47]

(1) If you're only interested in creation and destruction of WebContents, it is
possible to use 1 TriggerManager to do that. But if you want to implement
WebContentsObserver for other webcontents behavior (e.g. navigation), then 1
WebContentsObserver can only observe 1 WebContents. So eventually the mapping
will be
1 TriggerManager <--> n WebContentsObserver  <---> n WebContents

(2) Yes, you can get PrefService and incognito state from WebContents, but
calling code went through Profile. Typically, through
Profile::FromBrowserContext(web_contents->GetBrowserContext()). And then you can
do profile->GetPrefs() or profile->IsOffTheRecord().
Unfortunately, TriggerManager is in components/safe_browsing, which cannot
directly call Profile class. So the pref related decision need to be made
somewhere in chrome/browser/safe_browsing/ and passed into TriggerManager
somehow.
And if you're using a single TriggerManger to work with multiple profile, you
might need to keep track of these pref related decisions for each profile inside
TriggerManager.

Maybe initially, you can put TriggerManager inside chrome/browser/safe_browsing/
instead of putting it in the components?

[lpz, 2017/05/04 18:49:47]

As discussed offline, will keep it under components for now. Code that calls
into the TriggerManager (ie: tab_helpers) can do the job of accessing the
prefs/incoginto bits from the profile and pass them in a params. If we get stuck
needing other browser-level stuff later, there are ways to work around that at
that point.

+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  trigger_manager_ = base::MakeUnique<TriggerManager>();
+}
 }  // namespace safe_browsing