Make DOMStorageContextWrapper a client of memory coordinator

content/browser/dom_storage/dom_storage_context_wrapper.h

Index: content/browser/dom_storage/dom_storage_context_wrapper.h
diff --git a/content/browser/dom_storage/dom_storage_context_wrapper.h b/content/browser/dom_storage/dom_storage_context_wrapper.h
index 701324850accb5570bacdd80feabc529dc074dbb..f6b4afe18a7d7bd0ce12e4a9f43ae203c66a9913 100644
--- a/content/browser/dom_storage/dom_storage_context_wrapper.h
+++ b/content/browser/dom_storage/dom_storage_context_wrapper.h
@@ -11,6 +11,7 @@
 #include "base/macros.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ref_counted.h"
+#include "components/memory_coordinator/common/memory_coordinator_client.h"
 #include "content/common/content_export.h"
 #include "content/common/storage_partition_service.mojom.h"
 #include "content/public/browser/dom_storage_context.h"
@@ -37,7 +38,8 @@ class LevelDBWrapperImpl;
 // state.
 class CONTENT_EXPORT DOMStorageContextWrapper :
     NON_EXPORTED_BASE(public DOMStorageContext),
-    public base::RefCountedThreadSafe<DOMStorageContextWrapper> {
+    public base::RefCountedThreadSafe<DOMStorageContextWrapper>,
+    public memory_coordinator::MemoryCoordinatorClient {
  public:
   // If |data_path| is empty, nothing will be saved to disk.
   DOMStorageContextWrapper(
@@ -74,11 +76,14 @@ class CONTENT_EXPORT DOMStorageContextWrapper :
                         mojom::LevelDBObserverPtr observer,
                         mojom::LevelDBWrapperRequest request);
 
+ private:
   // Called on UI thread when the system is under memory pressure.
   void OnMemoryPressure(
       base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
 
- private:
+  // memory_coordinator::MemoryCoordinatorClient implementation:
+  void OnMemoryStateChange(memory_coordinator::MemoryState state) override;
+
   friend class DOMStorageMessageFilter;  // for access to context()

[michaeln, 2016/09/14 19:40:49]

nit: it'd be good to keep the two OnMem and PurgeMem methods together, also plz
keep the friend dcls up at the top of the private section, thnx

[hajimehoshi, 2016/09/15 09:14:46]

Done.

   friend class SessionStorageNamespaceImpl;  // ditto
   friend class base::RefCountedThreadSafe<DOMStorageContextWrapper>;
@@ -86,6 +91,8 @@ class CONTENT_EXPORT DOMStorageContextWrapper :
   ~DOMStorageContextWrapper() override;
   DOMStorageContextImpl* context() const { return context_.get(); }
 
+  void PurgeMemory(bool aggressively);
+
   // An inner class to keep all mojo-ish details together and not bleed them
   // through the public interface.
   class MojoState;