Remove readline support from d8.

src/d8.js

Index: src/d8.js
diff --git a/src/d8.js b/src/d8.js
index 65646f7bf2f0b03050368ab762665f73c47b2adb..8d55c788e2b42fa0d591ed146316c2c29dd9f365 100644
--- a/src/d8.js
+++ b/src/d8.js
@@ -4,51 +4,6 @@
 
 "use strict";
 
-String.prototype.startsWith = function (str) {
-  if (str.length > this.length) {
-    return false;
-  }
-  return this.substr(0, str.length) == str;
-};
-
-function ToInspectableObject(obj) {
-  if (!obj && typeof obj === 'object') {
-    return UNDEFINED;
-  } else {
-    return Object(obj);
-  }
-}
-
-function GetCompletions(global, last, full) {
-  var full_tokens = full.split();
-  full = full_tokens.pop();
-  var parts = full.split('.');
-  parts.pop();
-  var current = global;
-  for (var i = 0; i < parts.length; i++) {
-    var part = parts[i];
-    var next = current[part];
-    if (!next) {
-      return [];
-    }
-    current = next;
-  }
-  var result = [];
-  current = ToInspectableObject(current);
-  while (typeof current !== 'undefined') {
-    var mirror = new $debug.ObjectMirror(current);
-    var properties = mirror.properties();
-    for (var i = 0; i < properties.length; i++) {
-      var name = properties[i].name();
-      if (typeof name === 'string' && name.startsWith(last)) {
-        result.push(name);
-      }
-    }
-    current = ToInspectableObject(Object.getPrototypeOf(current));
-  }
-  return result;
-}
-
 // A more universal stringify that supports more types than JSON.
 // Used by the d8 shell to output results.
 var stringifyDepthLimit = 4;  // To avoid crashing on cyclic objects