[Media History] Enable media history feature behind a flag

Bug: 997813
Change-Id: I1cc6104341d131e3688c6167c430a14cb57f3337
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1903761
Commit-Queue: Evan Liu <evliu@google.com>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713988}

chrome/browser/media/history/OWNERS

 # TEAM: media-dev@chromium.org
 # COMPONENT: Internals>Media>History
 
-evliu@google.org
+evliu@google.com
 beccahughes@chromium.org
 steimel@chromium.org

chrome/browser/media/history/media_history_contents_observer.cc

@@ -9,19 +9,23 @@
 
 MediaHistoryContentsObserver::MediaHistoryContentsObserver(
     content::WebContents* web_contents)
-    : content::WebContentsObserver(web_contents) {
+    : content::WebContentsObserver(web_contents), service_(nullptr) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-
-  service_ = media_history::MediaHistoryKeyedServiceFactory::GetForProfile(
-      Profile::FromBrowserContext(web_contents->GetBrowserContext()));
-  DCHECK(service_);
+  Profile* profile =
+      Profile::FromBrowserContext(web_contents->GetBrowserContext());
+  if (!profile->IsOffTheRecord()) {
+    service_ =
+        media_history::MediaHistoryKeyedServiceFactory::GetForProfile(profile);
+    DCHECK(service_);
+  }
 }
 
 MediaHistoryContentsObserver::~MediaHistoryContentsObserver() = default;
 
 void MediaHistoryContentsObserver::MediaWatchTimeChanged(
     const content::MediaPlayerWatchTime& watch_time) {
-  service_->GetMediaHistoryStore()->SavePlayback(watch_time);
+  if (service_)
+    service_->GetMediaHistoryStore()->SavePlayback(watch_time);
 }
 
 WEB_CONTENTS_USER_DATA_KEY_IMPL(MediaHistoryContentsObserver)

chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc

@@ -37,6 +37,7 @@
 #include "chrome/browser/invalidation/deprecated_profile_invalidation_provider_factory.h"
 #include "chrome/browser/language/language_model_manager_factory.h"
 #include "chrome/browser/language/url_language_histogram_factory.h"
+#include "chrome/browser/media/history/media_history_keyed_service_factory.h"
 #include "chrome/browser/media/media_engagement_service.h"
 #include "chrome/browser/media/media_engagement_service_factory.h"
 #include "chrome/browser/media/router/media_router_factory.h"
@@ -88,6 +89,7 @@
 #include "components/safe_browsing/buildflags.h"
 #include "components/spellcheck/spellcheck_buildflags.h"
 #include "extensions/buildflags/buildflags.h"
+#include "media/base/media_switches.h"
 #include "ppapi/buildflags/buildflags.h"
 #include "printing/buildflags/buildflags.h"
 
@@ -294,6 +296,8 @@ void ChromeBrowserMainExtraPartsProfiles::
 #if !defined(OS_ANDROID)
   MediaGalleriesPreferencesFactory::GetInstance();
 #endif
+  if (base::FeatureList::IsEnabled(media::kUseMediaHistoryStore))
+    media_history::MediaHistoryKeyedServiceFactory::GetInstance();
 #if defined(OS_WIN) || defined(OS_MACOSX) || \
     (defined(OS_LINUX) && !defined(OS_CHROMEOS))
   metrics::DesktopProfileSessionDurationsServiceFactory::GetInstance();

chrome/browser/ui/tab_helpers.cc

@@ -28,6 +28,7 @@
 #include "chrome/browser/history/top_sites_factory.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/installable/installable_manager.h"
+#include "chrome/browser/media/history/media_history_contents_observer.h"
 #include "chrome/browser/media/media_engagement_service.h"
 #include "chrome/browser/metrics/desktop_session_duration/desktop_session_duration_observer.h"
 #include "chrome/browser/metrics/oom/out_of_memory_reporter.h"
@@ -99,6 +100,7 @@
 #include "components/ukm/content/source_url_recorder.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/buildflags/buildflags.h"
+#include "media/base/media_switches.h"
 #include "printing/buildflags/buildflags.h"
 
 #if defined(OS_ANDROID)
@@ -380,6 +382,9 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
   if (MediaEngagementService::IsEnabled())
     MediaEngagementService::CreateWebContentsObserver(web_contents);
 
+  if (base::FeatureList::IsEnabled(media::kUseMediaHistoryStore))
+    MediaHistoryContentsObserver::CreateForWebContents(web_contents);
+
   if (performance_manager::PerformanceManager::IsAvailable()) {
     performance_manager::PerformanceManagerTabHelper::CreateForWebContents(
         web_contents);