[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 486af1e008947ca8791be456b4c2d223bdc10d6f..129c63d3293ba2c47056e0105e43a662c3bf99ba 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"
@@ -93,6 +94,7 @@ struct DoConfigureSyncerTypes {
 
 class SyncBackendHostCore
     : public base::RefCountedThreadSafe<SyncBackendHostCore>,
+      public base::trace_event::MemoryDumpProvider,
       public SyncEncryptionHandler::Observer,
       public SyncManager::Observer,
       public TypeDebugInfoObserver {
@@ -102,6 +104,10 @@ 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.