Correct logic "Should ContextMenu target the selection?"

If the selection doesn't have focus, it shouldn't be the target
of the context menu.

For example, an _unfocused_ range selection should not be the
context menu's target (the focused element should be the target).

BUG=725005, 725022

Review-Url: https://codereview.chromium.org/2880313002
Cr-Commit-Position: refs/heads/master@{#473842}

third_party/WebKit/LayoutTests/fast/events/contextmenu-follows-focus.html

@@ -6,8 +6,19 @@ var contextForMenu;
 function catchContextMenu(event) {
   contextForMenu = event.currentTarget.tagName;
 }
+
+function focusLinkAndAssertLinkIsTargetOfContextMenu() {
+  eventSender.keyDown('Escape'); // Hide menu.
+  document.querySelector('A').focus();
+  contextForMenu = undefined;
+  eventSender.keyDown('ContextMenu');
+  assert_equals(contextForMenu, 'A',
+      'ContextMenu should use the focused link as target.');
+}
 </script>
 
+<div contenteditable oncontextmenu="catchContextMenu(event);">Some editable text.</div>
+<span oncontextmenu="catchContextMenu(event);">Some text to select.</span>
 <input oncontextmenu="catchContextMenu(event);">
 <a href="www" oncontextmenu="catchContextMenu(event);">A link</a>
 
@@ -18,15 +29,37 @@ test(function() {
   document.querySelector('INPUT').focus();
   eventSender.keyDown('ContextMenu');
   assert_equals(contextForMenu, 'INPUT',
-      'ContextMenu should use the focused input field as context.');
+      'ContextMenu should use the focused input field as target.');
+  focusLinkAndAssertLinkIsTargetOfContextMenu();
+}, 'ContextMenu should target the focused link (not the unfocused field).');
 
-  // Hide INPUT's context menu before we display A's context menu.
-  eventSender.keyDown('Escape');
+test(function() {
+  assert_exists(window, 'eventSender', 'This test requires eventSender.');
 
-  document.querySelector('A').focus();
+  document.querySelector('div').focus();
   eventSender.keyDown('ContextMenu');
-  assert_equals(contextForMenu, 'A',
-      'ContextMenu should use the focused link as context.');
+  assert_equals(contextForMenu, 'DIV',
+      'ContextMenu should use the editable div\'s caret as target.');
+  focusLinkAndAssertLinkIsTargetOfContextMenu();
+}, 'ContextMenu should target the focused link (not the div\'s caret).');
+
+test(function() {
+  assert_exists(window, 'eventSender', 'This test requires eventSender.');
+
+  const div = document.querySelector('div');
+  div.focus();
+  window.getSelection().selectAllChildren(div);
+  eventSender.keyDown('ContextMenu');
+  assert_equals(contextForMenu, 'DIV',
+      'ContextMenu should use the editable div\'s range selection as target.');
+  focusLinkAndAssertLinkIsTargetOfContextMenu();
+}, 'ContextMenu should target the focused link (not the div\'s selection).');
+
+test(function() {
+  assert_exists(window, 'eventSender', 'This test requires eventSender.');
 
-}, 'ContextMenu should always follow focused element.');
+  const span = document.querySelector('span');
+  window.getSelection().selectAllChildren(span);
+  focusLinkAndAssertLinkIsTargetOfContextMenu();
+}, 'ContextMenu should target the focused link (not the unfocused selection).');
 </script>

third_party/WebKit/Source/core/input/EventHandler.cpp

@@ -1802,6 +1802,14 @@ WebInputEventResult EventHandler::SendContextMenuEvent(
       event, mev.GetHitTestResult().CanvasRegionId(), 0);
 }
 
+static bool ShouldShowContextMenuAtSelection(const FrameSelection& selection) {
+  const VisibleSelection& visible_selection =
+      selection.ComputeVisibleSelectionInDOMTreeDeprecated();
+  if (!visible_selection.IsRange() && !visible_selection.RootEditableElement())
+    return false;
+  return selection.SelectionHasFocus();
+}
+
 WebInputEventResult EventHandler::SendContextMenuEventForKey(
     Element* override_target_element) {
   FrameView* view = frame_->View();
@@ -1824,14 +1832,9 @@ WebInputEventResult EventHandler::SendContextMenuEventForKey(
   Element* focused_element =
       override_target_element ? override_target_element : doc->FocusedElement();
   FrameSelection& selection = frame_->Selection();
-  Position start =
-      selection.ComputeVisibleSelectionInDOMTreeDeprecated().Start();
   VisualViewport& visual_viewport = frame_->GetPage()->GetVisualViewport();
 
-  if (!override_target_element && start.AnchorNode() && !selection.IsHidden() &&
-      (selection.ComputeVisibleSelectionInDOMTreeDeprecated()
-           .RootEditableElement() ||
-       selection.ComputeVisibleSelectionInDOMTreeDeprecated().IsRange())) {
+  if (!override_target_element && ShouldShowContextMenuAtSelection(selection)) {
     // TODO(editing-dev): Use of updateStyleAndLayoutIgnorePendingStylesheets
     // needs to be audited.  See http://crbug.com/590369 for more details.
     doc->UpdateStyleAndLayoutIgnorePendingStylesheets();