Make HostDiscardableSharedMemoryManager a client of memory coordinator

content/common/host_discardable_shared_memory_manager.h

Index: content/common/host_discardable_shared_memory_manager.h
diff --git a/content/common/host_discardable_shared_memory_manager.h b/content/common/host_discardable_shared_memory_manager.h
index fcbb35ae8eecef902d3ce4224ce252e5bbd27ab0..90c90938ceed8a705141276995348cd34ac898a6 100644
--- a/content/common/host_discardable_shared_memory_manager.h
+++ b/content/common/host_discardable_shared_memory_manager.h
@@ -17,6 +17,7 @@
 #include "base/macros.h"
 #include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/discardable_shared_memory.h"
+#include "base/memory/memory_coordinator_client.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory.h"
@@ -35,7 +36,8 @@ typedef int32_t DiscardableSharedMemoryId;
 // This class is thread-safe and instances can safely be used on any thread.
 class CONTENT_EXPORT HostDiscardableSharedMemoryManager
     : public base::DiscardableMemoryAllocator,
-      public base::trace_event::MemoryDumpProvider {
+      public base::trace_event::MemoryDumpProvider,
+      public base::MemoryCoordinatorClient {
  public:
   HostDiscardableSharedMemoryManager();
   ~HostDiscardableSharedMemoryManager() override;
@@ -103,6 +105,9 @@ class CONTENT_EXPORT HostDiscardableSharedMemoryManager
     return a->memory()->last_known_usage() > b->memory()->last_known_usage();
   }
 
+  // base::MemoryCoordinatorClient implementation:
+  void OnMemoryStateChange(base::MemoryState state) override;
+
   void AllocateLockedDiscardableSharedMemory(
       base::ProcessHandle process_handle,
       int client_process_id,