[sync] skeleton implementation of TypedURLSyncBridge

components/history/core/browser/history_backend.cc

Index: components/history/core/browser/history_backend.cc
diff --git a/components/history/core/browser/history_backend.cc b/components/history/core/browser/history_backend.cc
index 62187120cff3ae3d97a93a60b1fdcd8759dff2e5..32cbcefb06a11c32af73e213dd65568a1f0442e2 100644
--- a/components/history/core/browser/history_backend.cc
+++ b/components/history/core/browser/history_backend.cc
@@ -15,6 +15,8 @@
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
+#include "base/debug/dump_without_crashing.h"
+#include "base/feature_list.h"
 #include "base/files/file_enumerator.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
@@ -39,8 +41,10 @@
 #include "components/history/core/browser/in_memory_history_backend.h"
 #include "components/history/core/browser/keyword_search_term.h"
 #include "components/history/core/browser/page_usage_data.h"
+#include "components/history/core/browser/typed_url_sync_bridge.h"
 #include "components/history/core/browser/typed_url_syncable_service.h"
 #include "components/history/core/browser/url_utils.h"
+#include "components/sync/driver/sync_driver_switches.h"
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 #include "sql/error_delegate_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ -52,9 +56,11 @@
 #include "base/ios/scoped_critical_action.h"
 #endif
 
+using base::debug::DumpWithoutCrashing;
 using base::Time;
 using base::TimeDelta;
 using base::TimeTicks;
+using syncer::ModelTypeChangeProcessor;
 
 /* The HistoryBackend consists of two components:
 
@@ -211,7 +217,17 @@ void HistoryBackend::Init(
   if (!force_fail)
     InitImpl(history_database_params);
   delegate_->DBLoaded();
-  typed_url_syncable_service_.reset(new TypedUrlSyncableService(this));
+  if (base::FeatureList::IsEnabled(switches::kSyncUSSTypedURL)) {
+    typed_url_sync_bridge_ = base::MakeUnique<TypedURLSyncBridge>(
+        this,
+        base::BindRepeating(
+            &ModelTypeChangeProcessor::Create,
+            base::BindRepeating(base::IgnoreResult(&DumpWithoutCrashing))));

[skym, 2017/03/07 18:08:04]

Ugh. Okay, this is kind of a land mine that we're setting ourselves up for.
Typically we want to report 1% of errors on canary/dev. But this reports 100% on
all channels. We ultimately need to thread channel information into here similar
to what Max proposed in https://codereview.chromium.org/2647113002/. I really
wish we had a more convenient way of solving this.

Can you at least throw a big TODO in here explaining that this is mainly for
initial testing and needs to be fixed before launch?

[Gang Wu, 2017/03/31 19:35:58]

Done.

+  } else {
+    typed_url_syncable_service_ =
+        base::MakeUnique<TypedUrlSyncableService>(this);
+  }
+
   memory_pressure_listener_.reset(new base::MemoryPressureListener(
       base::Bind(&HistoryBackend::OnMemoryPressure, base::Unretained(this))));
 }
@@ -1031,6 +1047,10 @@ TypedUrlSyncableService* HistoryBackend::GetTypedUrlSyncableService() const {
   return typed_url_syncable_service_.get();
 }
 
+TypedURLSyncBridge* HistoryBackend::GetTypedURLSyncBridge() const {
+  return typed_url_sync_bridge_.get();
+}
+
 // Statistics ------------------------------------------------------------------
 
 HistoryCountResult HistoryBackend::GetHistoryCount(const Time& begin_time,