[Sync] Implement MemoryDumpProvider.

components/sync/driver/glue/sync_backend_host_core.h

Index: components/sync/driver/glue/sync_backend_host_core.h
diff --git a/components/sync/driver/glue/sync_backend_host_core.h b/components/sync/driver/glue/sync_backend_host_core.h
index 1af32252372671c3e720260eda82bc16115a0144..6f923afd1c5c0cb0e997ff018246312b2405cfe9 100644
--- a/components/sync/driver/glue/sync_backend_host_core.h
+++ b/components/sync/driver/glue/sync_backend_host_core.h
@@ -15,6 +15,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/timer/timer.h"
+#include "base/trace_event/memory_dump_provider.h"
 #include "components/invalidation/public/invalidation.h"
 #include "components/sync/base/cancelation_signal.h"
 #include "components/sync/base/system_encryptor.h"
@@ -89,6 +90,7 @@ struct DoConfigureSyncerTypes {
 
 class SyncBackendHostCore
     : public base::RefCountedThreadSafe<SyncBackendHostCore>,
+      public base::trace_event::MemoryDumpProvider,
       public SyncEncryptionHandler::Observer,
       public SyncManager::Observer,
       public TypeDebugInfoObserver {
@@ -98,6 +100,10 @@ class SyncBackendHostCore
                       bool has_sync_setup_completed,
                       const base::WeakPtr<SyncBackendHostImpl>& backend);
 
+  // MemoryDumpProvider implementation.
+  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
+                    base::trace_event::ProcessMemoryDump* pmd) override;
+
   // SyncManager::Observer implementation.  The Core just acts like an air
   // traffic controller here, forwarding incoming messages to appropriate
   // landing threads.