[Cronet] Add ExperimentalCronetEngine.Builder.setThreadPriority() API

components/cronet/android/java/src/org/chromium/net/impl/CronetUrlRequestContext.java

 // Copyright 2014 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.impl;
 
 import android.os.ConditionVariable;
 import android.os.Process;
 
 import org.chromium.base.Log;
@@ skipping 52 matching lines @@
     private long mUrlRequestContextAdapter = 0;
     /**
      * This field is accessed without synchronization, but only for the purposes of reference
      * equality comparison with other threads. If such a comparison is performed on the network
      * thread, then there is a happens-before edge between the write of this field and the
      * subsequent read; if it's performed on another thread, then observing a value of null won't
      * change the result of the comparison.
      */
     private Thread mNetworkThread;
 
-    private boolean mNetworkQualityEstimatorEnabled;
+    private final boolean mNetworkQualityEstimatorEnabled;
+    private final int mNetworkThreadPriority;
 
     /**
      * Locks operations on network quality listeners, because listener
      * addition and removal may occur on a different thread from notification.
      */
     private final Object mNetworkQualityLock = new Object();
 
     /**
      * Locks operations on the list of RequestFinishedInfo.Listeners, because operations can happen
      * on any thread. This should be used for fine-grained locking only. In particular, don't call
@@ skipping 57 matching lines @@
     private volatile ConditionVariable mStopNetLogCompleted;
 
     /**
      * True if a NetLog observer is active.
      */
     @GuardedBy("mLock")
     private boolean mIsLogging;
 
     @UsedByReflection("CronetEngine.java")
     public CronetUrlRequestContext(final CronetEngineBuilderImpl builder) {
+        mNetworkQualityEstimatorEnabled = builder.networkQualityEstimatorEnabled();
+        mNetworkThreadPriority = builder.threadPriority(Process.THREAD_PRIORITY_BACKGROUND);
         CronetLibraryLoader.ensureInitialized(builder.getContext(), builder);
         nativeSetMinLogLevel(getLoggingLevel());
         synchronized (mLock) {
             mUrlRequestContextAdapter =
                     nativeCreateRequestContextAdapter(createNativeUrlRequestContextConfig(builder));
             if (mUrlRequestContextAdapter == 0) {
                 throw new NullPointerException("Context Adapter creation failed.");
             }
-            mNetworkQualityEstimatorEnabled = builder.networkQualityEstimatorEnabled();
         }
 
         // Init native Chromium URLRequestContext on init thread.
         CronetLibraryLoader.postToInitThread(new Runnable() {
             @Override
             public void run() {
                 CronetLibraryLoader.ensureInitializedOnInitThread(builder.getContext());
                 synchronized (mLock) {
                     // mUrlRequestContextAdapter is guaranteed to exist until
                     // initialization on init and network threads completes and
@@ skipping 397 matching lines @@
                         "Internal Error: Illegal EffectiveConnectionType value " + type);
         }
     }
 
     @SuppressWarnings("unused")
     @CalledByNative
     private void initNetworkThread() {
         mNetworkThread = Thread.currentThread();
         mInitCompleted.open();
         Thread.currentThread().setName("ChromiumNet");
-        Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
+        Process.setThreadPriority(mNetworkThreadPriority);
     }
 
     @SuppressWarnings("unused")
     @CalledByNative
     private void onEffectiveConnectionTypeChanged(int effectiveConnectionType) {
         synchronized (mNetworkQualityLock) {
             // Convert the enum returned by the network quality estimator to an enum of type
             // EffectiveConnectionType.
             mEffectiveConnectionType = effectiveConnectionType;
         }
@@ skipping 124 matching lines @@
     @NativeClassQualifiedName("CronetURLRequestContextAdapter")
     private native void nativeProvideRTTObservations(long nativePtr, boolean should);
 
     @NativeClassQualifiedName("CronetURLRequestContextAdapter")
     private native void nativeProvideThroughputObservations(long nativePtr, boolean should);
 
     public boolean isNetworkThread(Thread thread) {
         return thread == mNetworkThread;
     }
 }