Make ProfileSyncService a client of memory coordinator

components/browser_sync/profile_sync_service.h

Index: components/browser_sync/profile_sync_service.h
diff --git a/components/browser_sync/profile_sync_service.h b/components/browser_sync/profile_sync_service.h
index f236e9a5f87d9d07837f20fe1739ff5bf1949f86..9d3667c28ea6878841a11a7b092e1e03bae474bc 100644
--- a/components/browser_sync/profile_sync_service.h
+++ b/components/browser_sync/profile_sync_service.h
@@ -16,6 +16,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/location.h"
 #include "base/macros.h"
+#include "base/memory/memory_coordinator_client.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
@@ -187,7 +188,8 @@ class ProfileSyncService : public sync_driver::SyncService,
                            public OAuth2TokenService::Consumer,
                            public OAuth2TokenService::Observer,
                            public SigninManagerBase::Observer,
-                           public GaiaCookieManagerService::Observer {
+                           public GaiaCookieManagerService::Observer,
+                           public base::MemoryCoordinatorClient {
  public:
   typedef SyncBackendHost::Status Status;
   typedef base::Callback<bool(void)> PlatformSyncAllowedProvider;
@@ -671,6 +673,11 @@ class ProfileSyncService : public sync_driver::SyncService,
 
   friend class TestProfileSyncService;
 
+  // base::MemoryCoordinatorClient implementation:
+  void OnMemoryStateChange(base::MemoryState state) override;
+
+  void IncrementMemoryPressureWarningCount();
+
   // Stops the sync engine. Does NOT set IsSyncRequested to false. Use
   // RequestStop for that. |data_fate| controls whether the local sync data is
   // deleted or kept when the engine shuts down.