Reland: Add MemoryCoordinator

components/memory_coordinator/browser/memory_coordinator.h

Index: components/memory_coordinator/browser/memory_coordinator.h
diff --git a/components/memory_coordinator/browser/memory_coordinator.h b/components/memory_coordinator/browser/memory_coordinator.h
new file mode 100644
index 0000000000000000000000000000000000000000..8ae02eb30943f45548830bf082973034965a932e
--- /dev/null
+++ b/components/memory_coordinator/browser/memory_coordinator.h
@@ -0,0 +1,42 @@
+// 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 COMPONENTS_MEMORY_COORDINATOR_BROWSER_MEMORY_COORDINATOR_H_
+#define COMPONENTS_MEMORY_COORDINATOR_BROWSER_MEMORY_COORDINATOR_H_
+
+#include "components/memory_coordinator/public/interfaces/memory_coordinator.mojom.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace memory_coordinator {
+
+class MemoryCoordinatorHandleImpl;
+
+// MemoryCoordinator is responsible for the whole memory management accross the
+// browser and child proceeses. It will dispatch memory events to its clients
+// and child processes based on its best knowledge of the memory usage.
+class MemoryCoordinator {
+ public:
+  MemoryCoordinator();
+  ~MemoryCoordinator();
+
+  void CreateHandle(int render_process_id,
+                    mojom::MemoryCoordinatorHandleRequest request);
+
+  // Returns number of children. Only used for testing.
+  size_t NumChildrenForTesting();
+
+ private:
+  void OnConnectionError(int render_process_id);
+
+  // Mappings of RenderProcessHost::GetID() -> MemoryCoordinatorHandleImpl.
+  // A mapping is added when a renderer connects to MemoryCoordinator and
+  // removed automatically when a underlying binding is disconnected.
+  std::map<int, std::unique_ptr<MemoryCoordinatorHandleImpl>> children_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryCoordinator);
+};
+
+}  // memory_coordinator
+
+#endif  // COMPONENTS_MEMORY_COORDINATOR_BROWSER_MEMORY_COORDINATOR_H_