[cc] Initial checkin of cc-frame-viewer

tools/cc-frame-viewer/src/ui/drag_handle.js

+/* 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.
+ */
+'use strict';
+
+base.require('ui');
+base.requireStylesheet('ui.drag_handle');
+
+base.exportTo('ui', function() {
+
+  /**
+   * Detects when user clicks handle determines new height of container based
+   * on user's vertical mouse move and resizes the target.
+   * @constructor
+   * @extends {HTMLDivElement}
+   * You will need to set target to be the draggable element
+   */
+  var DragHandle = ui.define('x-drag-handle');
+
+  DragHandle.prototype = {
+    __proto__: HTMLDivElement.prototype,
+
+    decorate: function() {
+      this.lastMousePosY = 0;
+      this.onMouseMove_ = this.onMouseMove_.bind(this);
+      this.onMouseUp_ = this.onMouseUp_.bind(this);
+      this.addEventListener('mousedown', this.onMouseDown_);
+      this.target = undefined;
+    },
+
+    onMouseMove_: function(e) {
+      // Compute the difference in height position.
+      var dy = this.lastMousePosY - e.clientY;
+      // If style is not set, start off with computed height.
+      if (!this.target.style.height)
+        this.target.style.height = window.getComputedStyle(this.target).height;
+      // Apply new height to the container.
+      this.target.style.height = parseInt(this.target.style.height) + dy + 'px';
+      this.lastMousePosY = e.clientY;
+      e.preventDefault();
+      return true;
+    },
+
+    onMouseDown_: function(e) {
+      if (!this.target)
+        return;
+      this.lastMousePosY = e.clientY;
+      document.addEventListener('mousemove', this.onMouseMove_);
+      document.addEventListener('mouseup', this.onMouseUp_);
+      e.preventDefault();
+      return true;
+    },
+
+    onMouseUp_: function(e) {
+      document.removeEventListener('mousemove', this.onMouseMove_);
+      document.removeEventListener('mouseup', this.onMouseUp_);
+      e.preventDefault();
+    }
+  };
+
+  return {
+    DragHandle: DragHandle
+  };
+});