Bug 1779269 - Fix AccessibleCaret's display on disabled form controls. r=emilio,webdriver-reviewers,whimboo

A disabled form controls cannot be focused, and its frame selection is different
from the one for not-editable content. Use GetLastFocusedFrameSelection() (added
in Bug 253870) to get the correct frame selection that is visible to the user.

Add some basic tests for disabled <textarea> such as long pressing to select,
dragging, etc. They should behave the same as normal <textarea>.

Differential Revision: https://phabricator.services.mozilla.com/D151800

layout/base/AccessibleCaretManager.cpp

@@ -820,23 +820,9 @@ already_AddRefed<nsFrameSelection> AccessibleCaretManager::GetFrameSelection()
     return nullptr;
   }
 
-  nsFocusManager* fm = nsFocusManager::GetFocusManager();
-  MOZ_ASSERT(fm);
-
-  nsIContent* focusedContent = fm->GetFocusedElement();
-  if (!focusedContent) {
-    // For non-editable content
-    return mPresShell->FrameSelection();
-  }
-
-  nsIFrame* focusFrame = focusedContent->GetPrimaryFrame();
-  if (!focusFrame) {
-    return nullptr;
-  }
-
   // Prevent us from touching the nsFrameSelection associated with other
   // PresShell.
-  RefPtr<nsFrameSelection> fs = focusFrame->GetFrameSelection();
+  RefPtr<nsFrameSelection> fs = mPresShell->GetLastFocusedFrameSelection();
   if (!fs || fs->GetPresShell() != mPresShell) {
     return nullptr;
   }

layout/base/tests/marionette/test_accessiblecaret_selection_mode.py

@@ -31,6 +31,7 @@ class AccessibleCaretSelectionModeTestCase(MarionetteTestCase):
     _input_size_id = "input-size"
     _textarea_id = "textarea"
     _textarea2_id = "textarea2"
+    _textarea_disabled_id = "textarea-disabled"
     _textarea_one_line_id = "textarea-one-line"
     _textarea_rtl_id = "textarea-rtl"
     _contenteditable_id = "contenteditable"
@@ -170,6 +171,7 @@ class AccessibleCaretSelectionModeTestCase(MarionetteTestCase):
 
     @parameterized(_input_id, el_id=_input_id)
     @parameterized(_textarea_id, el_id=_textarea_id)
+    @parameterized(_textarea_disabled_id, el_id=_textarea_disabled_id)
     @parameterized(_textarea_rtl_id, el_id=_textarea_rtl_id)
     @parameterized(_contenteditable_id, el_id=_contenteditable_id)
     @parameterized(_content_id, el_id=_content_id)
@@ -193,6 +195,7 @@ class AccessibleCaretSelectionModeTestCase(MarionetteTestCase):
 
     @parameterized(_input_id, el_id=_input_id)
     @parameterized(_textarea_id, el_id=_textarea_id)
+    @parameterized(_textarea_disabled_id, el_id=_textarea_disabled_id)
     @parameterized(_textarea_rtl_id, el_id=_textarea_rtl_id)
     @parameterized(_contenteditable_id, el_id=_contenteditable_id)
     @parameterized(_content_id, el_id=_content_id)
@@ -226,6 +229,7 @@ class AccessibleCaretSelectionModeTestCase(MarionetteTestCase):
 
     @parameterized(_input_id, el_id=_input_id)
     @parameterized(_textarea_id, el_id=_textarea_id)
+    @parameterized(_textarea_disabled_id, el_id=_textarea_disabled_id)
     @parameterized(_textarea_rtl_id, el_id=_textarea_rtl_id)
     @parameterized(_contenteditable_id, el_id=_contenteditable_id)
     @parameterized(_content_id, el_id=_content_id)
@@ -263,6 +267,7 @@ class AccessibleCaretSelectionModeTestCase(MarionetteTestCase):
 
     @parameterized(_input_id, el_id=_input_id)
     @parameterized(_textarea_id, el_id=_textarea_id)
+    @parameterized(_textarea_disabled_id, el_id=_textarea_disabled_id)
     @parameterized(_textarea_rtl_id, el_id=_textarea_rtl_id)
     @parameterized(_contenteditable_id, el_id=_contenteditable_id)
     @parameterized(_content_id, el_id=_content_id)
@@ -395,6 +400,7 @@ class AccessibleCaretSelectionModeTestCase(MarionetteTestCase):
 
     @parameterized(_input_id, el_id=_input_id)
     @parameterized(_textarea_id, el_id=_textarea_id)
+    @parameterized(_textarea_disabled_id, el_id=_textarea_disabled_id)
     @parameterized(_textarea_rtl_id, el_id=_textarea_rtl_id)
     @parameterized(_contenteditable_id, el_id=_contenteditable_id)
     @parameterized(_content_id, el_id=_content_id)

testing/marionette/harness/marionette_harness/www/layout/test_carets_selection.html

@@ -28,6 +28,7 @@
     <br>
     <div>
       <textarea id="textarea" rows="4" cols="8">ABC DEF GHI JKL MNO PQR</textarea>
+      <textarea id="textarea-disabled" rows="4" cols="8" disabled>ABC DEF GHI JKL MNO PQR</textarea>
       <textarea id="textarea-one-line" rows="4" cols="12">ABC DEF GHI</textarea>
     </div>
     <br>