Add MemoryCoordinatorImpl

content/browser/memory/memory_coordinator.h

Index: content/browser/memory/memory_coordinator.h
diff --git a/content/browser/memory/memory_coordinator.h b/content/browser/memory/memory_coordinator.h
index f674ef5b48ce950e5c442c24e73aef850940251d..47d695b570df3ef6a0b22cb717c610dd0d5b099d 100644
--- a/content/browser/memory/memory_coordinator.h
+++ b/content/browser/memory/memory_coordinator.h
@@ -6,7 +6,6 @@
 #define CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_H_
 
 #include "base/memory/memory_coordinator_client_registry.h"
-#include "base/memory/singleton.h"
 #include "base/process/process_handle.h"
 #include "content/common/content_export.h"
 #include "content/common/memory_coordinator.mojom.h"
@@ -24,7 +23,7 @@ class MemoryCoordinatorHandleImpl;
 // child processes based on its best knowledge of the memory usage.
 class CONTENT_EXPORT MemoryCoordinator {
  public:
-  ~MemoryCoordinator();
+  virtual ~MemoryCoordinator();
 
   // Singleton factory/accessor.
   static MemoryCoordinator* GetInstance();
@@ -59,14 +58,6 @@ class CONTENT_EXPORT MemoryCoordinator {
   // for testing.
   void OnConnectionError(int render_process_id);
 
- private:
-  friend struct base::DefaultSingletonTraits<MemoryCoordinator>;
-
-  // Helper function of CreateHandle and AddChildForTesting.
-  void CreateChildInfoMapEntry(
-      int render_process_id,
-      std::unique_ptr<MemoryCoordinatorHandleImpl> handle);
-
   // Stores information about any known child processes.
   struct ChildInfo {
     // This object must be compatible with STL containers.
@@ -81,6 +72,17 @@ class CONTENT_EXPORT MemoryCoordinator {
   // A map from process ID (RenderProcessHost::GetID()) to child process info.
   using ChildInfoMap = std::map<int, ChildInfo>;
 
+  ChildInfoMap& children() { return children_; }
+
+  virtual void OnChildAdded() {}
+  virtual void OnChildRemoved() {}

[chrisha, 2016/09/30 02:57:20]

Why are these needed? The Impl should be able to infer that a child has been
added or removed by inspecting the map, and need not react immediately.

+
+private:
+  // Helper function of CreateHandle and AddChildForTesting.
+  void CreateChildInfoMapEntry(
+      int render_process_id,
+      std::unique_ptr<MemoryCoordinatorHandleImpl> handle);
+
   // Tracks child processes. An entry is added when a renderer connects to
   // MemoryCoordinator and removed automatically when an underlying binding is
   // disconnected.
@@ -89,6 +91,26 @@ class CONTENT_EXPORT MemoryCoordinator {
   DISALLOW_COPY_AND_ASSIGN(MemoryCoordinator);
 };
 
+// The implementation of MemoryCoordinatorHandle. See memory_coordinator.mojom
+// for the role of this class.
+class MemoryCoordinatorHandleImpl : public mojom::MemoryCoordinatorHandle {

[chrisha, 2016/09/30 02:57:20]

Why do we need to expose this impl detail?

+ public:
+  MemoryCoordinatorHandleImpl(mojom::MemoryCoordinatorHandleRequest request);
+  ~MemoryCoordinatorHandleImpl() override;
+
+  // mojom::MemoryCoordinatorHandle:
+  void AddChild(mojom::ChildMemoryCoordinatorPtr child) override;
+
+  mojom::ChildMemoryCoordinatorPtr& child() { return child_; }
+  mojo::Binding<mojom::MemoryCoordinatorHandle>& binding() { return binding_; }
+
+ private:
+  mojom::ChildMemoryCoordinatorPtr child_;
+  mojo::Binding<mojom::MemoryCoordinatorHandle> binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryCoordinatorHandleImpl);
+};
+
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_H_