[Cronet] Move initialization to a new thread rather than the UI thread.

net/android/java/src/org/chromium/net/ProxyChangeListener.java

Index: net/android/java/src/org/chromium/net/ProxyChangeListener.java
diff --git a/net/android/java/src/org/chromium/net/ProxyChangeListener.java b/net/android/java/src/org/chromium/net/ProxyChangeListener.java
index 1ccf7a597247dfef1e7c1e5daadbdeef7253f39e..503e2eaeb996a0c8459f10830a11f015c88a38f2 100644
--- a/net/android/java/src/org/chromium/net/ProxyChangeListener.java
+++ b/net/android/java/src/org/chromium/net/ProxyChangeListener.java
@@ -11,9 +11,12 @@ import android.content.IntentFilter;
 import android.net.Proxy;
 import android.net.Uri;
 import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
 import android.text.TextUtils;
 import android.util.Log;
 
+import org.chromium.base.BuildConfig;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
@@ -31,6 +34,9 @@ public class ProxyChangeListener {
     private static final String TAG = "ProxyChangeListener";
     private static boolean sEnabled = true;
 
+    private final Looper mLooper;
+    private final Handler mHandler;
+
     private long mNativePtr;
     private ProxyReceiver mProxyReceiver;
     private Delegate mDelegate;
@@ -55,7 +61,10 @@ public class ProxyChangeListener {
         public void proxySettingsChanged();
     }
 
-    private ProxyChangeListener() {}
+    private ProxyChangeListener() {
+        mLooper = Looper.myLooper();
+        mHandler = new Handler(mLooper);
+    }
 
     public static void setEnabled(boolean enabled) {
         sEnabled = enabled;
@@ -77,6 +86,7 @@ public class ProxyChangeListener {
 
     @CalledByNative
     public void start(long nativePtr) {
+        assertOnThread();
         assert mNativePtr == 0;
         mNativePtr = nativePtr;
         registerReceiver();
@@ -84,15 +94,21 @@ public class ProxyChangeListener {
 
     @CalledByNative
     public void stop() {
+        assertOnThread();
         mNativePtr = 0;
         unregisterReceiver();
     }
 
     private class ProxyReceiver extends BroadcastReceiver {
         @Override
-        public void onReceive(Context context, Intent intent) {
+        public void onReceive(Context context, final Intent intent) {
             if (intent.getAction().equals(Proxy.PROXY_CHANGE_ACTION)) {
-                proxySettingsChanged(extractNewProxy(intent));
+                runOnThread(new Runnable() {
+                    @Override
+                    public void run() {
+                        proxySettingsChanged(ProxyReceiver.this, extractNewProxy(intent));
+                    }
+                });
             }
         }
 
@@ -173,8 +189,12 @@ public class ProxyChangeListener {
         }
     }
 
-    private void proxySettingsChanged(ProxyConfig cfg) {
-        if (!sEnabled) {
+    private void proxySettingsChanged(ProxyReceiver proxyReceiver, ProxyConfig cfg) {
+        if (!sEnabled
+                // Once execution begins on the correct thread, make sure unregisterReceiver()
+                // hasn't been called in the mean time. Ignore the changed signal if
+                // unregisterReceiver() was called.
+                || proxyReceiver != mProxyReceiver) {
             return;
         }
         if (mDelegate != null) {
@@ -211,6 +231,24 @@ public class ProxyChangeListener {
         mProxyReceiver = null;
     }
 
+    private boolean onThread() {
+        return mLooper == Looper.myLooper();
+    }
+
+    private void assertOnThread() {
+        if (BuildConfig.DCHECK_IS_ON && !onThread()) {
+            throw new IllegalStateException("Must be called on ProxyChangeListener thread.");
+        }
+    }
+
+    private void runOnThread(Runnable r) {
+        if (onThread()) {
+            r.run();
+        } else {
+            mHandler.post(r);
+        }
+    }
+
     /**
      * See net/proxy/proxy_config_service_android.cc
      */