ProfileSyncService::InitParams: initialize all members

Let's make sure all the raw pointers are properly nulled out rather than
uninitialized. I'm not aware of any concrete problems caused by this,
but better safe than sorry.

Bug: none (AFAIK)
Change-Id: Ifae536ad37858ae264e055106bf6c2d80c2567e3
Reviewed-on: https://chromium-review.googlesource.com/c/1317606Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605313}

components/browser_sync/profile_sync_service.h

@@ -200,7 +200,7 @@ class ProfileSyncService : public syncer::SyncService,
     ~InitParams();
 
     std::unique_ptr<syncer::SyncClient> sync_client;
-    identity::IdentityManager* identity_manager;
+    identity::IdentityManager* identity_manager = nullptr;
     SigninScopedDeviceIdCallback signin_scoped_device_id_callback;
     GaiaCookieManagerService* gaia_cookie_manager_service = nullptr;
     std::vector<invalidation::IdentityProvider*>
@@ -208,7 +208,7 @@ class ProfileSyncService : public syncer::SyncService,
     StartBehavior start_behavior = MANUAL_START;
     syncer::NetworkTimeUpdateCallback network_time_update_callback;
     scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory;
-    network::NetworkConnectionTracker* network_connection_tracker;
+    network::NetworkConnectionTracker* network_connection_tracker = nullptr;
     std::string debug_identifier;
     version_info::Channel channel = version_info::Channel::UNKNOWN;
     bool user_events_separate_pref_group = false;