[android_webview] Don't block the IO thread when reading from an InputStream.

android_webview/unittestjava/src/org/chromium/android_webview/unittest/InputStreamUnittest.java

+// Copyright (c) 2012 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.android_webview.unittest;
+
+import org.chromium.base.CalledByNative;
+
+import java.io.InputStream;
+import java.io.IOException;
+
+class InputStreamUnittest {
+  private InputStreamUnittest() {
+  }
+
+  @CalledByNative
+  static InputStream getEmptyStream() {
+      return new InputStream() {
+          @Override
+          public int read() {
+              return -1;
+          }
+      };
+  }
+
+  @CalledByNative
+  static InputStream getCountingStream(final int size) {
+      return new InputStream() {
+          private int count = 0;
+
+          @Override
+          public int read() {
+              if (count < size)
+                  return count++ % 256;
+              else
+                  return -1;
+          }
+      };
+  }
+}