DevTools: clicking in console messages should not jump to bottom

third_party/WebKit/Source/devtools/front_end/console/ConsoleView.js

 /*
  * Copyright (C) 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 97 matching lines @@
     if (!this._showSettingsPaneSetting.get())
       settingsPane.element.classList.add('hidden');
     this._showSettingsPaneSetting.addChangeListener(
         () => settingsPane.element.classList.toggle('hidden', !this._showSettingsPaneSetting.get()));
 
     this._viewport = new Console.ConsoleViewport(this);
     this._viewport.setStickToBottom(true);
     this._viewport.contentElement().classList.add('console-group', 'console-group-messages');
     this._contentsElement.appendChild(this._viewport.element);
     this._messagesElement = this._viewport.element;
+    this._messagesElement.tabIndex = -1;

[luoe, 2017/04/24 22:28:33]

Currently on ToT, using up/down/pageup/pagedown keys in the console viewport no
longer scrolls.  By doing this, the viewport is focusable, restoring the old
behavior.  I haven't done a bisect yet to find out when it broke.

     this._messagesElement.id = 'console-messages';
     this._messagesElement.classList.add('monospace');
     this._messagesElement.addEventListener('click', this._messagesClicked.bind(this), true);
 
     this._viewportThrottler = new Common.Throttler(50);
 
     this._topGroup = Console.ConsoleGroup.createTopGroup();
     this._currentGroup = this._topGroup;
 
     this._promptElement = this._messagesElement.createChild('div', 'source-code');
@@ skipping 174 matching lines @@
   wasShown() {
     this._viewport.refresh();
   }
 
   /**
    * @override
    */
   focus() {
     if (this._prompt.hasFocus())
       return;
-    // Set caret position before setting focus in order to avoid scrolling
-    // by focus().

[luoe, 2017/04/24 22:28:33]

This is no longer the case.  Calling moveCaretToEndOfPrompt() will always try to
scroll.

     this._prompt.moveCaretToEndOfPrompt();
     this._prompt.focus();
   }
 
   /**
    * @override
    */
   restoreScrollPositions() {
     if (this._viewport.stickToBottom())
       this._immediatelyScrollToBottom();
@@ skipping 335 matching lines @@
     this._updateFilterStatus();
     this._searchableView.updateSearchMatchesCount(this._regexMatchRanges.length);
     this._viewport.invalidate();
   }
 
   /**
    * @param {!Event} event
    */
   _messagesClicked(event) {
     var targetElement = event.deepElementFromPoint();
-    if (!targetElement || targetElement.isComponentSelectionCollapsed())
+    if (!targetElement || this._viewport.element.isScrolledToBottom())
       this.focus();

[luoe, 2017/04/24 22:28:33]

I think we still need to keep 2 paths.  When you click on the whitespace
underneath the prompt, it should still move the prompt cursor to the end, which
is the behavior on stable.

+    else if (targetElement.isComponentSelectionCollapsed())
+      this._prompt.focus();
+
     var groupMessage = event.target.enclosingNodeOrSelfWithClass('console-group-title');
     if (!groupMessage)
       return;
     var consoleGroupViewMessage = groupMessage.parentElement.message;
     consoleGroupViewMessage.setCollapsed(!consoleGroupViewMessage.collapsed());
     this._updateMessageList();
   }
 
   _registerShortcuts() {
     this._shortcuts = {};
@@ skipping 591 matching lines @@
         return true;
     }
     return false;
   }
 };
 
 /**
  * @typedef {{messageIndex: number, matchIndex: number}}
  */
 Console.ConsoleView.RegexMatchRange;