Add HttpUrlConnection backed implementation of CronetEngine.

components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.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;
 
 import android.os.SystemClock;
 import android.support.annotation.Nullable;
 import android.util.Log;
 
@@ skipping 238 matching lines @@
         }
     }
 
     @Override
     public void read(ByteBuffer buffer) {
         synchronized (mUrlRequestAdapterLock) {
             if (buffer.position() >= buffer.capacity()) {
                 throw new IllegalArgumentException(
                         "ByteBuffer is already full.");
             }
+            Preconditions.checkDirect(buffer);
 
             if (!mWaitingOnRead) {
                 throw new IllegalStateException("Unexpected read attempt.");
             }
             mWaitingOnRead = false;
             mLegacyReadByteBufferAdjustment = true;
 
             if (isDone()) {
                 return;
             }
 
             // Indicate buffer has no new data. This is primarily to make it
             // clear the buffer has no data in the failure and completion cases.
             buffer.limit(buffer.position());
 
             if (!nativeReadData(mUrlRequestAdapter, buffer, buffer.position(),
                     buffer.capacity())) {
                 // Still waiting on read. This is just to have consistent
                 // behavior with the other error cases.
                 mWaitingOnRead = true;
-                // Since accessing byteBuffer's memory failed, it's presumably
-                // not a direct ByteBuffer.
-                throw new IllegalArgumentException(
-                        "byteBuffer must be a direct ByteBuffer.");
+                throw new IllegalArgumentException("Unable to call native read");
             }
         }
     }
 
     @Override
     public void readNew(ByteBuffer buffer) {
+        Preconditions.checkHasRemaining(buffer);
+        Preconditions.checkDirect(buffer);
         synchronized (mUrlRequestAdapterLock) {
-            if (!buffer.hasRemaining()) {
-                throw new IllegalArgumentException("ByteBuffer is already full.");
-            }
-
             if (!mWaitingOnRead) {
                 throw new IllegalStateException("Unexpected read attempt.");
             }
             mWaitingOnRead = false;
             mLegacyReadByteBufferAdjustment = false;
 
             if (isDone()) {
                 return;
             }
 
             if (!nativeReadData(mUrlRequestAdapter, buffer, buffer.position(), buffer.limit())) {
                 // Still waiting on read. This is just to have consistent
                 // behavior with the other error cases.
                 mWaitingOnRead = true;
-                // Since accessing byteBuffer's memory failed, it's presumably
-                // not a direct ByteBuffer.
-                throw new IllegalArgumentException("byteBuffer must be a direct ByteBuffer.");
+                throw new IllegalArgumentException("Unable to call native read");
             }
         }
     }
 
     @Override
     public void cancel() {
         synchronized (mUrlRequestAdapterLock) {
             if (isDone() || !mStarted) {
                 return;
             }
@@ skipping 464 matching lines @@
 
     @NativeClassQualifiedName("CronetURLRequestAdapter")
     private native String nativeGetProxyServer(long nativePtr);
 
     @NativeClassQualifiedName("CronetURLRequestAdapter")
     private native void nativeGetStatus(long nativePtr, UrlRequest.StatusListener listener);
 
     @NativeClassQualifiedName("CronetURLRequestAdapter")
     private native boolean nativeGetWasCached(long nativePtr);
 }