Sync MDP: implement MemoryDumpProvider

components/sync/core/sync_manager.h

Index: components/sync/core/sync_manager.h
diff --git a/components/sync/core/sync_manager.h b/components/sync/core/sync_manager.h
index 5f3d1aff3a8a2d5e2c30cc2c5888040a9e95dec1..451988e94fd5ef42656f3314faa6b8b567f63cd8 100644
--- a/components/sync/core/sync_manager.h
+++ b/components/sync/core/sync_manager.h
@@ -35,6 +35,12 @@
 
 class GURL;
 
+namespace base {
+namespace trace_event {
+class ProcessMemoryDump;
+}
+}
+
 namespace sync_pb {
 class EncryptedData;
 }  // namespace sync_pb
@@ -336,6 +342,9 @@ class SyncManager {
   // Status-related getter.  May be called on any thread.
   virtual SyncStatus GetDetailedStatus() const = 0;
 
+  // Adds memory usage statistics to |pmd| for chrome://tracing.
+  virtual void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) = 0;
+
   // Call periodically from a database-safe thread to persist recent changes
   // to the syncapi model.
   virtual void SaveChanges() = 0;