DevTools: introduce WebInspector.Throttler

Source/devtools/front_end/common/Throttler.js

Index: Source/devtools/front_end/common/Throttler.js
diff --git a/Source/devtools/front_end/common/Throttler.js b/Source/devtools/front_end/common/Throttler.js
new file mode 100644
index 0000000000000000000000000000000000000000..2a3a8969dba4125c51f172f7b34fa50008bac0c2
--- /dev/null
+++ b/Source/devtools/front_end/common/Throttler.js
@@ -0,0 +1,47 @@
+// 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.
+
+/**
+ * @constructor
+ * @param {number} timeout
+ */
+WebInspector.Throttler = function(timeout)
+{
+    this._timeout = timeout;
+    this._isRunningProcess = false;
+    this._somethingScheduled = false;
+}
+
+WebInspector.Throttler.prototype = {
+    _processCompleted: function()
+    {
+        this._isRunningProcess = false;
+        if (this._somethingScheduled)
+            this.schedule(this._process);
+    },
+
+    _onProcessTimeout: function()
+    {
+        this._processTimeout = null;
+        this._somethingScheduled = false;
+        this._isRunningProcess = true;
+        this._process(this._processCompleted.bind(this));
+    },
+
+    /**
+     * @param {function(function())} process
+     */
+    schedule: function(process)
+    {
+        this._somethingScheduled = true;
+        this._process = process;
+
+        if (this._isRunningProcess)
+            return;
+
+        if (!this._processTimeout)
+            this._processTimeout = setTimeout(this._onProcessTimeout.bind(this), this._timeout);
+    }
+}
+