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..0b8e48b80a0cec73531cb0c9d850f3c5dd0bc2d6 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 +46,20 @@ class CronetUrlRequestContext extends UrlRequestContext {
     private long mUrlRequestContextAdapter = 0;
     private Thread mNetworkThread;
 
+    private Executor mNetworkQualityExecutor;
+
+    // Locks operations on network quality observers, because observer addition and removal may

[tbansal1, 2015/09/15 17:10:24]

May be javadoc style comments?
/**
 *
 */

[bengr, 2015/09/16 15:32:38]

Done.

+    // occur on a different thread from notification.
+    private final Object mNetworkQualityLock = new Object();
+
+    @GuardedBy("mNetworkQualityLock")
+    private final ObserverList<NetworkQualityRttObserver> mRttObserverList =
+            new ObserverList<NetworkQualityRttObserver>();
+
+    @GuardedBy("mNetworkQualityLock")
+    private final ObserverList<NetworkQualityThroughputObserver> mThroughputObserverList =
+            new ObserverList<NetworkQualityThroughputObserver>();
+
     @UsedByReflection("UrlRequestContext.java")
     public CronetUrlRequestContext(Context context,
                                    UrlRequestContextConfig config) {
@@ -148,6 +166,75 @@ class CronetUrlRequestContext extends UrlRequestContext {
         }
     }
 
+    @Override
+    public void enableNetworkQualityEstimator(Executor executor) {
+        enableNetworkQualityEstimator(false, false, executor);
+    }
+
+    @VisibleForTesting
+    @Override
+    void enableNetworkQualityEstimator(
+            boolean useLocalHostRequests, boolean useSmallerResponses, Executor executor) {
+        mNetworkQualityExecutor = executor;
+        synchronized (mLock) {
+            checkHaveAdapter();
+            nativeEnableNetworkQualityEstimator(
+                    mUrlRequestContextAdapter, useLocalHostRequests, useSmallerResponses);
+        }
+    }
+
+    @Override
+    public void addRttObserver(NetworkQualityRttObserver observer) {
+        synchronized (mNetworkQualityLock) {
+            if (mRttObserverList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideRTTObservations(mUrlRequestContextAdapter, true);
+                }
+            }
+            mRttObserverList.addObserver(observer);
+        }
+    }
+
+    @Override
+    public void removeRttObserver(NetworkQualityRttObserver observer) {
+        synchronized (mNetworkQualityLock) {
+            mRttObserverList.removeObserver(observer);
+            if (mRttObserverList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideRTTObservations(mUrlRequestContextAdapter, false);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void addThroughputObserver(NetworkQualityThroughputObserver observer) {
+        synchronized (mNetworkQualityLock) {
+            if (mThroughputObserverList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideThroughputObservations(mUrlRequestContextAdapter, true);
+                }
+            }
+            mThroughputObserverList.addObserver(observer);
+        }
+    }
+
+    @Override
+    public void removeThroughputObserver(NetworkQualityThroughputObserver observer) {
+        synchronized (mNetworkQualityLock) {
+            mThroughputObserverList.removeObserver(observer);
+            if (mThroughputObserverList.isEmpty()) {
+                synchronized (mLock) {
+                    checkHaveAdapter();
+                    nativeProvideThroughputObservations(mUrlRequestContextAdapter, false);
+                }
+            }
+        }
+    }
+
     /**
      * Mark request as started to prevent shutdown when there are active
      * requests.
@@ -209,6 +296,45 @@ class CronetUrlRequestContext extends UrlRequestContext {
         Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
     }
 
+    @SuppressWarnings("unused")

[tbansal1, 2015/09/15 17:10:24]

Why does it need SuppressWarnings. Looks like it is called by
cronet_url_request_context_adapter.cc.

[bengr, 2015/09/16 15:32:38]

Following the pattern for other methods that are called by native.

+    @CalledByNative
+    private void onRttObservation(final int value, final long when, final int source) {

[tbansal1, 2015/09/15 17:10:24]

Why not whenMs here and below?

[bengr, 2015/09/16 15:32:38]

Done.

+        Runnable task = new Runnable() {
+            @Override
+            public void run() {
+                for (NetworkQualityRttObserver observer : mRttObserverList) {
+                    observer.onRttObservation(value, when, source);
+                }
+            }
+        };
+        postObservationTaskToExecutor(task);
+    }
+
+    @SuppressWarnings("unused")
+    @CalledByNative
+    private void onThroughputObservation(final int value, final long when, final int source) {
+        Runnable task = new Runnable() {
+            @Override
+            public void run() {
+                for (NetworkQualityThroughputObserver observer : mThroughputObserverList) {
+                    observer.onThroughputObservation(value, when, source);
+                }
+            }
+        };
+        postObservationTaskToExecutor(task);
+    }
+
+    void postObservationTaskToExecutor(Runnable task) {
+        try {
+            synchronized (mNetworkQualityLock) {
+                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 +352,14 @@ 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);
 }