[Cronet] Separate Cronet implementation and API by package name.

components/cronet/android/java/src/org/chromium/net/CronetLibraryLoader.java

-// Copyright 2015 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.net;
-
-import android.content.Context;
-import android.os.Handler;
-import android.os.Looper;
-
-import org.chromium.base.ContextUtils;
-import org.chromium.base.Log;
-import org.chromium.base.annotations.JNINamespace;
-
-/**
- * CronetLibraryLoader loads and initializes native library on main thread.
- */
-@JNINamespace("cronet")
-class CronetLibraryLoader {
-    // Synchronize initialization.
-    private static final Object sLoadLock = new Object();
-    private static final String TAG = "CronetLibraryLoader";
-    // Has library loading commenced?  Setting guarded by sLoadLock.
-    private static volatile boolean sInitStarted = false;
-    // Has ensureMainThreadInitialized() completed?  Only accessed on main thread.
-    private static boolean sMainThreadInitDone = false;
-
-    /**
-     * Ensure that native library is loaded and initialized. Can be called from
-     * any thread, the load and initialization is performed on main thread.
-     */
-    static void ensureInitialized(final Context context, final CronetEngine.Builder builder) {
-        synchronized (sLoadLock) {
-            if (sInitStarted) {
-                return;
-            }
-            sInitStarted = true;
-            ContextUtils.initApplicationContext(context.getApplicationContext());
-            builder.loadLibrary();
-            ContextUtils.initApplicationContextForNative();
-            if (!Version.CRONET_VERSION.equals(nativeGetCronetVersion())) {
-                throw new RuntimeException(String.format(
-                      "Expected Cronet version number %s, "
-                              + "actual version number %s.",
-                      Version.CRONET_VERSION,
-                      nativeGetCronetVersion()));
-            }
-            Log.i(TAG, "Cronet version: %s, arch: %s",
-                    Version.CRONET_VERSION, System.getProperty("os.arch"));
-            // Init native Chromium CronetEngine on Main UI thread.
-            Runnable task = new Runnable() {
-                @Override
-                public void run() {
-                    ensureInitializedOnMainThread(context);
-                }
-            };
-            // Run task immediately or post it to the UI thread.
-            if (Looper.getMainLooper() == Looper.myLooper()) {
-                task.run();
-            } else {
-                // The initOnMainThread will complete on the main thread prior
-                // to other tasks posted to the main thread.
-                new Handler(Looper.getMainLooper()).post(task);
-            }
-        }
-    }
-
-    /**
-     * Ensure that the main thread initialization has completed. Can only be called from
-     * the main thread. Ensures that the NetworkChangeNotifier is initialzied and the
-     * main thread native MessageLoop is initialized.
-     */
-    static void ensureInitializedOnMainThread(Context context) {
-        assert sInitStarted;
-        assert Looper.getMainLooper() == Looper.myLooper();
-        if (sMainThreadInitDone) {
-            return;
-        }
-        NetworkChangeNotifier.init(context);
-        // Registers to always receive network notifications. Note
-        // that this call is fine for Cronet because Cronet
-        // embedders do not have API access to create network change
-        // observers. Existing observers in the net stack do not
-        // perform expensive work.
-        NetworkChangeNotifier.registerToReceiveNotificationsAlways();
-        // registerToReceiveNotificationsAlways() is called before the native
-        // NetworkChangeNotifierAndroid is created, so as to avoid receiving
-        // the undesired initial network change observer notification, which
-        // will cause active requests to fail with ERR_NETWORK_CHANGED.
-        nativeCronetInitOnMainThread();
-        sMainThreadInitDone = true;
-    }
-
-    // Native methods are implemented in cronet_library_loader.cc.
-    private static native void nativeCronetInitOnMainThread();
-    private static native String nativeGetCronetVersion();
-}