Eliminate OmniboxMetricsProvider listening to notification

chrome/browser/metrics/omnibox_metrics_provider.cc

 // Copyright 2014 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/metrics/omnibox_metrics_provider.h"
 
 #include <vector>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/ui/browser_otr_state.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/proto/omnibox_event.pb.h"
 #include "components/metrics/proto/omnibox_input_type.pb.h"
 #include "components/omnibox/browser/autocomplete_match.h"
 #include "components/omnibox/browser/autocomplete_provider.h"
 #include "components/omnibox/browser/autocomplete_result.h"
 #include "components/omnibox/browser/omnibox_log.h"
-#include "content/public/browser/notification_service.h"
 
 using metrics::OmniboxEventProto;
 
 namespace {
 
 OmniboxEventProto::Suggestion::ResultType AsOmniboxEventResultType(
     AutocompleteMatch::Type type) {
   switch (type) {
     case AutocompleteMatchType::URL_WHAT_YOU_TYPED:
       return OmniboxEventProto::Suggestion::URL_WHAT_YOU_TYPED;
@@ skipping 41 matching lines @@
 
 }  // namespace
 
 OmniboxMetricsProvider::OmniboxMetricsProvider() {
 }
 
 OmniboxMetricsProvider::~OmniboxMetricsProvider() {
 }
 
 void OmniboxMetricsProvider::OnRecordingEnabled() {
-  registrar_.Add(this, chrome::NOTIFICATION_OMNIBOX_OPENED_URL,
-                 content::NotificationService::AllSources());
+  subscription_ = OmniboxEventGlobalTracker::GetInstance()->RegisterCallback(
+      base::Bind(&OmniboxMetricsProvider::OnURLOpenedFromOmnibox,
+                 base::Unretained(this)));

[Alexei Svitkine (slow), 2015/08/06 19:29:03]

Nit: Use a weak ptr factory.

[Peter Kasting, 2015/08/06 19:58:22]

Why is that needed?  Isn't the fact that |subscription_| is a scoped_ptr
sufficient?

[blundell, 2015/08/06 20:22:21]

Peter's right: base::CallbackList removes the callback from the list when the
returned subscription is destroyed.

[Alexei Svitkine (slow), 2015/08/06 20:27:28]

Oops, you're right.

 }
 
 void OmniboxMetricsProvider::OnRecordingDisabled() {
-  registrar_.RemoveAll();
+  subscription_.reset();
 }
 
 void OmniboxMetricsProvider::ProvideGeneralMetrics(
     metrics::ChromeUserMetricsExtension* uma_proto) {
   uma_proto->mutable_omnibox_event()->Swap(
       omnibox_events_cache.mutable_omnibox_event());
 }
 
-void OmniboxMetricsProvider::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_OMNIBOX_OPENED_URL, type);
-
+void OmniboxMetricsProvider::OnURLOpenedFromOmnibox(OmniboxLog* log) {
   // We simply don't log events to UMA if there is a single incognito
   // session visible. In the future, it may be worth revisiting this to
   // still log events from non-incognito sessions.
   if (!chrome::IsOffTheRecordSessionActive())
-    RecordOmniboxOpenedURL(*content::Details<OmniboxLog>(details).ptr());
+    RecordOmniboxOpenedURL(*log);
 }
 
 void OmniboxMetricsProvider::RecordOmniboxOpenedURL(const OmniboxLog& log) {
   std::vector<base::StringPiece16> terms = base::SplitStringPiece(
       log.text, base::kWhitespaceUTF16,
       base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
 
   OmniboxEventProto* omnibox_event = omnibox_events_cache.add_omnibox_event();
   omnibox_event->set_time(metrics::MetricsLog::GetCurrentTime());
   if (log.tab_id != -1) {
@@ skipping 38 matching lines @@
     if (i->typed_count != -1)
       suggestion->set_typed_count(i->typed_count);
   }
   for (ProvidersInfo::const_iterator i(log.providers_info.begin());
        i != log.providers_info.end(); ++i) {
     OmniboxEventProto::ProviderInfo* provider_info =
         omnibox_event->add_provider_info();
     provider_info->CopyFrom(*i);
   }
 }