Added Network Quality Estimator Real-time interface to Cronet

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

Index: components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
diff --git a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
index 7bae2883221d5340a4ddbb23c19c9bf4865d978a..cd4b710f7c710b296620ba6ed0e150261833bf48 100644
--- a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
+++ b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
@@ -12,6 +12,7 @@ import android.os.Looper;
 import android.os.Process;
 import android.util.Log;
 
+import org.chromium.base.ObserverList;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
@@ -19,8 +20,11 @@ import org.chromium.base.annotations.NativeClassQualifiedName;
 import org.chromium.base.annotations.UsedByReflection;
 
 import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import javax.annotation.concurrent.GuardedBy;
+
 /**
  * UrlRequestContext using Chromium HTTP stack implementation.
  */
@@ -42,6 +46,22 @@ class CronetUrlRequestContext extends UrlRequestContext {
     private long mUrlRequestContextAdapter = 0;
     private Thread mNetworkThread;
 
+    private Executor mNetworkQualityExecutor;
+    private boolean mNetworkQualityEstimatorEnabled;
+
+    /** 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();
+
+    @GuardedBy("mNetworkQualityLock")
+    private final ObserverList<NetworkQualityRttListener> mRttListenerList =
+            new ObserverList<NetworkQualityRttListener>();
+
+    @GuardedBy("mNetworkQualityLock")
+    private final ObserverList<NetworkQualityThroughputListener> mThroughputListenerList =
+            new ObserverList<NetworkQualityThroughputListener>();
+
     @UsedByReflection("UrlRequestContext.java")
     public CronetUrlRequestContext(Context context,
                                    UrlRequestContextConfig config) {
@@ -148,6 +168,94 @@ class CronetUrlRequestContext extends UrlRequestContext {
         }
     }
 
+    @Override
+    public void enableNetworkQualityEstimator(Executor executor) {
+        enableNetworkQualityEstimatorForTesting(false, false, executor);
+    }
+
+    @VisibleForTesting
+    @Override
+    void enableNetworkQualityEstimatorForTesting(
+            boolean useLocalHostRequests, boolean useSmallerResponses, Executor executor) {
+        if (mNetworkQualityEstimatorEnabled) {
+            throw new IllegalStateException("Network quality estimator already enabled");
+        }
+        mNetworkQualityEstimatorEnabled = true;
+        if (executor == null) {
+            throw new NullPointerException("Network quality estimator requires an executor");
+        }
+        mNetworkQualityExecutor = executor;
+        synchronized (mLock) {
+            checkHaveAdapter();
+            nativeEnableNetworkQualityEstimator(
+                    mUrlRequestContextAdapter, useLocalHostRequests, useSmallerResponses);
+        }
+    }
+
+    @Override
+    public void addRttListener(NetworkQualityRttListener listener) {
+        if (!mNetworkQualityEstimatorEnabled) {
+            throw new IllegalStateException("Network quality estimator must be enabled");
+        }
+        synchronized (mNetworkQualityLock) {
+            if (mRttListenerList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideRTTObservations(mUrlRequestContextAdapter, true);
+                }
+            }
+            mRttListenerList.addObserver(listener);
+        }
+    }
+
+    @Override
+    public void removeRttListener(NetworkQualityRttListener listener) {
+        if (!mNetworkQualityEstimatorEnabled) {
+            throw new IllegalStateException("Network quality estimator must be enabled");
+        }
+        synchronized (mNetworkQualityLock) {
+            mRttListenerList.removeObserver(listener);
+            if (mRttListenerList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideRTTObservations(mUrlRequestContextAdapter, false);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void addThroughputListener(NetworkQualityThroughputListener listener) {
+        if (!mNetworkQualityEstimatorEnabled) {
+            throw new IllegalStateException("Network quality estimator must be enabled");
+        }
+        synchronized (mNetworkQualityLock) {
+            if (mThroughputListenerList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideThroughputObservations(mUrlRequestContextAdapter, true);
+                }
+            }
+            mThroughputListenerList.addObserver(listener);
+        }
+    }
+
+    @Override
+    public void removeThroughputListener(NetworkQualityThroughputListener listener) {
+        if (!mNetworkQualityEstimatorEnabled) {
+            throw new IllegalStateException("Network quality estimator must be enabled");
+        }
+        synchronized (mNetworkQualityLock) {
+            mThroughputListenerList.removeObserver(listener);
+            if (mThroughputListenerList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideThroughputObservations(mUrlRequestContextAdapter, false);
+                }
+            }
+        }
+    }
+
     /**
      * Mark request as started to prevent shutdown when there are active
      * requests.
@@ -209,6 +317,48 @@ class CronetUrlRequestContext extends UrlRequestContext {
         Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
     }
 
+    @SuppressWarnings("unused")
+    @CalledByNative
+    private void onRttObservation(final int rttMs, final long whenMs, final int source) {
+        Runnable task = new Runnable() {
+            @Override
+            public void run() {
+                synchronized (mNetworkQualityLock) {
+                    for (NetworkQualityRttListener listener : mRttListenerList) {
+                        listener.onRttObservation(rttMs, whenMs, source);
+                    }
+                }
+            }
+        };
+        postObservationTaskToNetworkQualityExecutor(task);
+    }
+
+    @SuppressWarnings("unused")
+    @CalledByNative
+    private void onThroughputObservation(
+            final int throughputKbps, final long whenMs, final int source) {
+        Runnable task = new Runnable() {
+            @Override
+            public void run() {
+                synchronized (mNetworkQualityLock) {
+                    for (NetworkQualityThroughputListener listener : mThroughputListenerList) {
+                        listener.onThroughputObservation(throughputKbps, whenMs, source);
+                    }
+                }
+            }
+        };
+        postObservationTaskToNetworkQualityExecutor(task);
+    }
+
+    void postObservationTaskToNetworkQualityExecutor(Runnable task) {
+        try {
+            mNetworkQualityExecutor.execute(task);
+        } catch (RejectedExecutionException failException) {
+            Log.e(CronetUrlRequestContext.LOG_TAG, "Exception posting task to executor",
+                    failException);
+        }
+    }
+
     // Native methods are implemented in cronet_url_request_context.cc.
     private static native long nativeCreateRequestContextAdapter(String config);
 
@@ -226,4 +376,14 @@ class CronetUrlRequestContext extends UrlRequestContext {
 
     @NativeClassQualifiedName("CronetURLRequestContextAdapter")
     private native void nativeInitRequestContextOnMainThread(long nativePtr);
+
+    @NativeClassQualifiedName("CronetURLRequestContextAdapter")
+    private native void nativeEnableNetworkQualityEstimator(
+            long nativePtr, boolean useLocalHostRequests, boolean useSmallerResponses);
+
+    @NativeClassQualifiedName("CronetURLRequestContextAdapter")
+    private native void nativeProvideRTTObservations(long nativePtr, boolean should);
+
+    @NativeClassQualifiedName("CronetURLRequestContextAdapter")
+    private native void nativeProvideThroughputObservations(long nativePtr, boolean should);
 }