Add MemoryCoordinatorDelegate

content/browser/memory/memory_coordinator.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_H_
 #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"
+#include "content/public/browser/memory_coordinator_delegate.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 namespace content {
 
 // NOTE: Memory coordinator is under development and not fully working.
 // TODO(bashi): Add more explanations when we implement memory coordinator V0.
 
 class MemoryCoordinatorHandleImpl;
 
 // MemoryCoordinator is responsible for the whole memory management accross the
 // browser and child proceeses. It dispatches memory events to its clients and
 // child processes based on its best knowledge of the memory usage.
 class CONTENT_EXPORT MemoryCoordinator {
  public:
   ~MemoryCoordinator();
 
   // Singleton factory/accessor.
   static MemoryCoordinator* GetInstance();
 
+  void SetDelegate(const base::WeakPtr<MemoryCoordinatorDelegate>& delegate) {
+    delegate_ = delegate;
+  }
+
   // Creates a handle to the provided child process.
   void CreateHandle(int render_process_id,
                     mojom::MemoryCoordinatorHandleRequest request);
 
   // Returns number of children. Only used for testing.
   size_t NumChildrenForTesting();
 
   // Dispatches a memory state change to the provided process. Returns true if
   // the process is tracked by this coordinator and successfully dispatches,
   // returns false otherwise.
@@ skipping 10 matching lines @@
   MemoryCoordinator();
 
   // Adds the given ChildMemoryCoordinator as a child of this coordinator.
   void AddChildForTesting(int dummy_render_process_id,
                           mojom::ChildMemoryCoordinatorPtr child);
 
   // Callback invoked by mojo when the child connection goes down. Exposed
   // for testing.
   void OnConnectionError(int render_process_id);
 
+  // Returns true when a given renderer can be suspended.
+  bool CanSuspendRenderer(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.
     ChildInfo();
     ChildInfo(const ChildInfo& rhs);
     ~ChildInfo();
 
     mojom::MemoryState memory_state;
     std::unique_ptr<MemoryCoordinatorHandleImpl> handle;
   };
 
   // A map from process ID (RenderProcessHost::GetID()) to child process info.
   using ChildInfoMap = std::map<int, ChildInfo>;
 
   // Tracks child processes. An entry is added when a renderer connects to
   // MemoryCoordinator and removed automatically when an underlying binding is
   // disconnected.
   ChildInfoMap children_;
 
+  base::WeakPtr<MemoryCoordinatorDelegate> delegate_;

[haraken, 2016/10/07 06:38:19]

Why does this need to be a WeakPtr?

[bashi, 2016/10/07 07:13:37]

TabManager (which is effectively the only implementation of the delegate) isn't
a permanent object and we can't control its life cycle from here. Passing a raw
pointer is dangerous.

[haraken, 2016/10/07 07:31:07]

I'll defer the decision to Chris -- how the lifetime relationship between MC and
TabManager should be.

[bashi, 2016/10/07 07:34:01]

Just to clarify: This is a tentative workaround. When we move logic from
TabManager to a separate delegate, we can MC owns the delegate.

+
   DISALLOW_COPY_AND_ASSIGN(MemoryCoordinator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_H_