Use parent SlowBuffer, if any, when Buffer is sliced

Closes #3416
Closes #3477

lib/buffer.js

@@ -210,8 +210,12 @@ function Buffer(subject, encoding, offset) {
 
   // Are we slicing?
   if (typeof offset === 'number') {
+    if (!Buffer.isBuffer(subject)) {
+      throw new Error('First argument must be a Buffer when slicing');
+    }
+
     this.length = coerce(encoding);
-    this.parent = subject;
+    this.parent = subject.parent ? subject.parent : subject;
     this.offset = offset;
   } else {
     // Find the length

test/simple/test-buffer.js

@@ -724,3 +724,6 @@ var a = Buffer(3);
 var b = Buffer('xxx');
 a.write('aaaaaaaa', 'base64');
 assert.equal(b.toString(), 'xxx');
+
+// issue GH-3416
+Buffer(Buffer(0), 0, 0);