[Cronet] Check whether request is done before spinning up message loop

components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.java

Index: components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.java
diff --git a/components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.java b/components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.java
index e5a7090c3faca500d76507538e6d0100292bf8d2..1367a2de537e9d2eb5faf010674013137dfdd565 100644
--- a/components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.java
+++ b/components/cronet/android/java/src/org/chromium/net/urlconnection/CronetBufferedOutputStream.java
@@ -71,18 +71,18 @@ final class CronetBufferedOutputStream extends CronetOutputStream {
 
     @Override
     public void write(int oneByte) throws IOException {
+        checkNotClosed();
         ensureCanWrite(1);
         mBuffer.put((byte) oneByte);
     }
 
     @Override
     public void write(byte[] buffer, int offset, int count) throws IOException {
+        checkNotClosed();
         ensureCanWrite(count);
         mBuffer.put(buffer, offset, count);
     }
 
-    // TODO(xunjieli): implement close().
-
     /**
      * Ensures that {@code count} bytes can be written to the internal buffer.
      */