Reland: Add MemoryCoordinator

components/memory_coordinator/browser/memory_coordinator.cc

Index: components/memory_coordinator/browser/memory_coordinator.cc
diff --git a/components/memory_coordinator/browser/memory_coordinator.cc b/components/memory_coordinator/browser/memory_coordinator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..101426f828009212bbe48d04334377d3dc63eeb0
--- /dev/null
+++ b/components/memory_coordinator/browser/memory_coordinator.cc
@@ -0,0 +1,56 @@
+// 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.
+
+#include "components/memory_coordinator/browser/memory_coordinator.h"
+
+namespace memory_coordinator {
+
+// The implementation of MemoryCoordinatorHandle. See memory_coordinator.mojom
+// for the role of this class.
+class MemoryCoordinatorHandleImpl : public mojom::MemoryCoordinatorHandle {
+ public:
+  MemoryCoordinatorHandleImpl(mojom::MemoryCoordinatorHandleRequest request)
+      : binding_(this, std::move(request)) {
+  }
+
+  // mojom::MemoryCoordinatorHandle implementations:
+
+  void AddChild(mojom::ChildMemoryCoordinatorPtr child) override {
+    DCHECK(!child_.is_bound());
+    child_ = std::move(child);
+  }
+
+  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);
+};
+
+MemoryCoordinator::MemoryCoordinator() {}
+
+MemoryCoordinator::~MemoryCoordinator() {}
+
+void MemoryCoordinator::CreateHandle(
+    int render_process_id,
+    mojom::MemoryCoordinatorHandleRequest request) {
+  auto handle = new MemoryCoordinatorHandleImpl(std::move(request));
+  handle->binding().set_connection_error_handler(
+      base::Bind(&MemoryCoordinator::OnConnectionError, base::Unretained(this),
+                 render_process_id));
+  children_[render_process_id].reset(handle);
+}
+
+size_t MemoryCoordinator::NumChildrenForTesting() {
+  return children_.size();
+}
+
+void MemoryCoordinator::OnConnectionError(int render_process_id) {
+  children_.erase(render_process_id);
+}
+
+}  // namespace memory_coordinator