Moving BindingManager and ChildProcessConnection to base/.

content/public/android/java/src/org/chromium/content/browser/BindingManager.java

-// Copyright 2013 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.
-
-package org.chromium.content.browser;
-
-import android.content.Context;
-
-/**
- * Manages oom bindings used to bound child services. "Oom binding" is a binding that raises the
- * process oom priority so that it shouldn't be killed by the OS out-of-memory killer under
- * normal conditions (it can still be killed under drastic memory pressure). ChildProcessConnections
- * have two oom bindings: initial binding and strong binding.
- *
- * BindingManager receives calls that signal status of each service (setInForeground(),
- * determinedVisibility()) and the entire embedding application (onSentToBackground(),
- * onBroughtToForeground()) and manipulates child process bindings accordingly.
- *
- * In particular, BindingManager is responsible for:
- * - adding and removing the strong binding as service visibility changes (setInForeground())
- * - removing the initial binding of a service when we can start to rely on the visibility signal /
- *   strong binding exclusively (after determinedVisibility())
- * - dropping the current oom bindings when a new connection is started on a low-memory device
- * - keeping a strong binding on the foreground service while the entire application is in
- *   background
- *
- * Thread-safety: most of the methods will be called only on the main thread, exceptions are
- * explicitly noted.
- */
-public interface BindingManager {
-    /**
-     * Registers a freshly started child process. This can be called on any thread.
-     * @param pid handle of the service process
-     */
-    void addNewConnection(int pid, ManagedChildProcessConnection connection);
-
-    /**
-     * Called when the service visibility changes or is determined for the first time. On low-memory
-     * devices this will also drop the oom bindings of the last process that was oom-bound if a new
-     * process is used in foreground.
-     * @param pid handle of the service process
-     * @param inForeground true iff the service is visibile to the user
-     */
-    void setInForeground(int pid, boolean inForeground);
-
-    /**
-     * Called when we can begin to rely on the visibility signal only and remove the initial
-     * binding. It's safe to call it multiple times, only the first call matters.
-     * @param pid handle of the service process
-     */
-    void onDeterminedVisibility(int pid);
-
-    /**
-     * Called when the embedding application is sent to background. We want to maintain a strong
-     * binding on the most recently used renderer while the embedder is in background, to indicate
-     * the relative importance of the renderer to system oom killer.
-     *
-     * The embedder needs to ensure that:
-     *  - every onBroughtToForeground() is followed by onSentToBackground()
-     *  - pairs of consecutive onBroughtToForeground() / onSentToBackground() calls do not overlap
-     */
-    void onSentToBackground();
-
-    /**
-     * Called when the embedding application is brought to foreground. This will drop the strong
-     * binding kept on the main renderer during the background period, so the embedder should make
-     * sure that this is called after the regular strong binding is attached for the foreground
-     * session.
-     */
-    void onBroughtToForeground();
-
-    /**
-     * Should be called when the connection to the child process goes away (either after a clean
-     * exit or an unexpected crash). At this point we let go of the reference to the
-     * ChildProcessConnection. This can be called on any thread.
-     */
-    void removeConnection(int pid);
-
-    /**
-     * Starts moderate binding management.
-     * Please see https://goo.gl/tl9MQm for details.
-     */
-    void startModerateBindingManagement(Context context, int maxSize);
-
-    /**
-     * Releases all moderate bindings.
-     */
-    void releaseAllModerateBindings();
-}