memory coordinator: Throttle background renderers on Android

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/memory_pressure_monitor.h"
 #include "base/process/process_handle.h"
@@ skipping 82 matching lines @@
     mojom::MemoryState memory_state;
     bool is_visible = false;
     std::unique_ptr<MemoryCoordinatorHandleImpl> handle;
   };
 
   // A map from process ID (RenderProcessHost::GetID()) to child process info.
   using ChildInfoMap = std::map<int, ChildInfo>;
 
   ChildInfoMap& children() { return children_; }
 
-private:
+ private:
 #if !defined(OS_MACOSX)
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorTest, HandleAdded);
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorTest, CanSuspendRenderer);
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorTest, CanThrottleRenderer);
 #endif
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorTest,
                            ChildRemovedOnConnectionError);
+  FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorTest, SetChildMemoryState);
+
+  // Called by SetChildMemoryState() to determine a child memory state based on
+  // the current status of the child process.
+  mojom::MemoryState OverrideChildState(mojom::MemoryState memroy_state,
+                                        const ChildInfo& child);
 
   void SetDelegateForTesting(
       std::unique_ptr<MemoryCoordinatorDelegate> delegate);
 
   // 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.
   ChildInfoMap children_;
 
   std::unique_ptr<MemoryCoordinatorDelegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryCoordinator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_H_