[Sync] Add interface and backend impl for typed URL syncable service

chrome/browser/history/history_backend.cc

Index: chrome/browser/history/history_backend.cc
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 327896b44682c53e6ce3694ddcd1d2473361bc52..16635bfdb7bb8506bd7533dadd6bc23b1562a5c9 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -33,6 +33,7 @@
 #include "chrome/browser/history/page_usage_data.h"
 #include "chrome/browser/history/select_favicon_frames.h"
 #include "chrome/browser/history/top_sites.h"
+#include "chrome/browser/history/typed_url_syncable_service.h"
 #include "chrome/browser/history/visit_filter.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_notification_types.h"
@@ -296,6 +297,7 @@ void HistoryBackend::Init(const std::string& languages, bool force_fail) {
   if (!force_fail)
     InitImpl(languages);
   delegate_->DBLoaded(id_);
+  typed_url_syncable_service_.reset(new TypedUrlSyncableService(this));
 }
 
 void HistoryBackend::SetOnBackendDestroyTask(MessageLoop* message_loop,
@@ -1174,6 +1176,10 @@ void HistoryBackend::QueryURL(scoped_refptr<QueryURLRequest> request,
   request->ForwardResult(request->handle(), success, row, visits);
 }
 
+TypedUrlSyncableService* HistoryBackend::GetTypedUrlSyncableService() const {
+  return typed_url_syncable_service_.get();
+}
+
 // Segment usage ---------------------------------------------------------------
 
 void HistoryBackend::DeleteOldSegmentData() {
@@ -2860,11 +2866,35 @@ void HistoryBackend::BroadcastNotifications(
     int type,
     HistoryDetails* details_deleted) {
   // |delegate_| may be NULL if |this| is in the process of closing (closed by
-  // HistoryService -> HistroyBackend::Closing().
-  if (delegate_.get())
+  // HistoryService -> HistoryBackend::Closing().
+  if (delegate_.get()) {
+    // Typed urls sync service is called here to handle deleted urls, including
+    // expirations from ExpireHistoryBackend, new, modified, and visited urls
+    if (typed_url_syncable_service_.get()) {
+      switch (type) {
+        case chrome::NOTIFICATION_HISTORY_URLS_DELETED: {

[brettw, 2013/04/20 05:14:18]

I don't think it makes sense to key off of the notification inside the history
system itself on the same thread. We're trying to delete the notification
service, and using this exceedingly weak coupling inside of one logical
subsystem unnecessarily declarifies things.

Maybe one thing that would be better would be to add these functions on the
delegate interface with the necessary parameters, and have the backend create
the details and issue the notification.

[mgist1, 2013/04/22 20:47:05]

Just to clarify, would it be better to remove this code completely from
BroadcastNotifications and instead call the necessary handler from within the
code that calls BroadcastNotifications (the way the code was before Patch Set
7), and in addition have a wrapper function within
BroadcastNotificationDelegate, implemented by HistoryBackend, to take details
from ExpireHistoryBackend and call OnUrlsDeleted?

+          typed_url_syncable_service_->OnUrlsDeleted(
+              static_cast<history::URLsDeletedDetails*>(details_deleted));
+          break;
+        }
+        case chrome::NOTIFICATION_HISTORY_URLS_MODIFIED: {
+          typed_url_syncable_service_->OnUrlsModified(
+              static_cast<history::URLsModifiedDetails*>(details_deleted));
+          break;
+        }
+        case chrome::NOTIFICATION_HISTORY_URL_VISITED: {
+          typed_url_syncable_service_->OnUrlVisited(
+              static_cast<history::URLVisitedDetails*>(details_deleted));
+          break;
+        }
+        default:
+          break;
+      }
+    }
     delegate_->BroadcastNotifications(type, details_deleted);
-  else
+  } else {
     delete details_deleted;
+  }
 }
 
 // Deleting --------------------------------------------------------------------