Fix window-exiting drags and drag-and-hold behaviors in JX.Scrollbar

Summary:
Fixes two issues:

  - In Firefox, dragging outside the window and releasing the mouse button would miss the `mouseup` event. This would leave the bar dragging, even though the user had released the mouse button.
  - In all browsers, dragging the handle and then holding your cursor in one place for more than a second would hide the handle. Instead, never hide the handle during a drag.

Test Plan:
  - In Firefox, dragged handle right (outside of window) and released mouse button. Waved cursor over window; no more "sticky" scroll.
  - In FF/Chrome/Safari, dragged handle and held cursor in same position for several seconds. No more handle hide.
  - Waved cursor over window and made sure normal hiding still works.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D11487

resources/celerity/map.php

@@ -166,7 +166,7 @@ return array(
     'rsrc/externals/javelin/core/__tests__/install.js' => 'c432ee85',
     'rsrc/externals/javelin/core/__tests__/stratcom.js' => '88bf7313',
     'rsrc/externals/javelin/core/__tests__/util.js' => 'e251703d',
-    'rsrc/externals/javelin/core/init.js' => '8c4e8f8b',
+    'rsrc/externals/javelin/core/init.js' => '4df97779',
     'rsrc/externals/javelin/core/init_node.js' => 'c234aded',
     'rsrc/externals/javelin/core/install.js' => '05270951',
     'rsrc/externals/javelin/core/util.js' => '93cc50d6',
@@ -199,7 +199,7 @@ return array(
     'rsrc/externals/javelin/lib/Resource.js' => '44959b73',
     'rsrc/externals/javelin/lib/Routable.js' => 'b3e7d692',
     'rsrc/externals/javelin/lib/Router.js' => '29274e2b',
-    'rsrc/externals/javelin/lib/Scrollbar.js' => '8ebeb833',
+    'rsrc/externals/javelin/lib/Scrollbar.js' => 'ad2c4a94',
     'rsrc/externals/javelin/lib/URI.js' => '6eff08aa',
     'rsrc/externals/javelin/lib/Vector.js' => 'cc1bd0b0',
     'rsrc/externals/javelin/lib/WebSocket.js' => '3f840822',
@@ -663,7 +663,7 @@ return array(
     'javelin-install' => '05270951',
     'javelin-json' => '69adf288',
     'javelin-leader' => '331b1611',
-    'javelin-magical-init' => '8c4e8f8b',
+    'javelin-magical-init' => '4df97779',
     'javelin-mask' => '8a41885b',
     'javelin-reactor' => '2b8de964',
     'javelin-reactor-dom' => 'c90a04fc',
@@ -673,7 +673,7 @@ return array(
     'javelin-resource' => '44959b73',
     'javelin-routable' => 'b3e7d692',
     'javelin-router' => '29274e2b',
-    'javelin-scrollbar' => '8ebeb833',
+    'javelin-scrollbar' => 'ad2c4a94',
     'javelin-stratcom' => '8b0ad945',
     'javelin-tokenizer' => '7644823e',
     'javelin-typeahead' => '70baed2f',
@@ -1468,12 +1468,6 @@ return array(
       'javelin-stratcom',
       'javelin-behavior',
     ),
-    '8ebeb833' => array(
-      'javelin-install',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-vector',
-    ),
     '8ef9ab58' => array(
       'javelin-behavior',
       'javelin-dom',
@@ -1582,6 +1576,12 @@ return array(
       'javelin-util',
       'phabricator-prefab',
     ),
+    'ad2c4a94' => array(
+      'javelin-install',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-vector',
+    ),
     'ad7a69ca' => array(
       'javelin-install',
       'javelin-util',

webroot/rsrc/externals/javelin/core/init.js

@@ -132,7 +132,6 @@
     'mousedown',
     'mouseover',
     'mouseout',
-    'mouseup',
     'keyup',
     'keydown',
     'input',
@@ -172,8 +171,8 @@
     JX.enableDispatch(root, document_events[ii]);
   }
 
-  //  In particular, we're interested in capturing window focus/blur here so
-  //  long polls can abort when the window is not focused.
+  // In particular, we're interested in capturing window focus/blur here so
+  // long polls can abort when the window is not focused.
   var window_events = [
     ('onpagehide' in window) ? 'pagehide' : 'unload',
     'resize',
@@ -181,7 +180,12 @@
     'focus',
     'blur',
     'popstate',
-    'hashchange'
+    'hashchange',
+
+    // In Firefox, if the user clicks in the window then drags the cursor
+    // outside of the window and releases the mouse button, we don't get this
+    // event unless we listen for it as a window event.
+    'mouseup'
   ];
 
   if (window.localStorage) {

webroot/rsrc/externals/javelin/lib/Scrollbar.js

@@ -238,6 +238,9 @@ JX.install('Scrollbar', {
      */
     _ondrop: function() {
       this._dragOrigin = null;
+
+      // Reset the timer to hide the bar.
+      this._showBar();
     },
 
 
@@ -293,6 +296,12 @@ JX.install('Scrollbar', {
      * Hide the scrollbar.
      */
     _hideBar: function() {
+      if (this._dragOrigin !== null) {
+        // If we're currently dragging the handle, we never want to hide
+        // it.
+        return;
+      }
+
       JX.DOM.alterClass(this._handle, 'jx-scrollbar-visible', false);
       this._clearTimeout();
     },