Focused nodes should never be ignored

This work is required before we can merge the two position classes: AXNodePosition and BrowserAccessibilityPosition.

This patch fixes AXNode::IsIgnored so that it won't mark focused nodes as ignored.
This is for consistency with AXNode::IsVisibleOrIgnored.
The merged AXPosition class will need to rely on IsIgnored extensively and there shouldn't
be a mismatch with platform code that uses IsInvisibleOrIgnored.

Also improves method comments and simplifies the name of
AXNode::IsFocusedWithinThisTree.

R=dmazzoni@chromium.org, aleventhal@chromium.org

AX-Relnotes: n/a.
Bug: 1049261
Change-Id: Ic8fc261b10afcf5db2a458bf9081e17036ccc82d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2637596Reviewed-by: Kurt Catti-Schmidt <kschmi@microsoft.com>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845791}

ui/accessibility/ax_node.cc

@@ -1246,7 +1246,7 @@ std::string AXNode::GetValueForTextField() const {
 }
 
 bool AXNode::IsIgnored() const {
-  return data().IsIgnored();
+  return data().IsIgnored() && !IsFocusedInThisTree();
 }
 
 bool AXNode::IsIgnoredForTextNavigation() const {
@@ -1254,13 +1254,10 @@ bool AXNode::IsIgnoredForTextNavigation() const {
 }
 
 bool AXNode::IsInvisibleOrIgnored() const {
-  if (!data().IsInvisibleOrIgnored())
-    return false;
-
-  return !IsFocusedWithinThisTree();
+  return data().IsInvisibleOrIgnored() && !IsFocusedInThisTree();
 }
 
-bool AXNode::IsFocusedWithinThisTree() const {
+bool AXNode::IsFocusedInThisTree() const {
   return id() == tree_->data().focus_id;
 }
 

ui/accessibility/ax_node.h

@@ -456,7 +456,8 @@ class AX_EXPORT AXNode final {
   // element.
   bool IsEmbeddedGroup() const;
 
-  // Returns true if node has ignored state or ignored role.
+  // Returns true if this node has the ignored state or the ignored role.
+  // Focused nodes are, by design, not ignored.
   bool IsIgnored() const;
 
   // Some nodes are not ignored but should be skipped during text navigation.
@@ -464,11 +465,14 @@ class AX_EXPORT AXNode final {
   // encountering a splitter during character and word navigation.
   bool IsIgnoredForTextNavigation() const;
 
-  // Returns true if node is invisible or ignored.
+  // Returns true if node is invisible, or if it is ignored as determined by
+  // `AXNode::IsIgnored()`.
   bool IsInvisibleOrIgnored() const;
 
-  // Returns true if node is focused within this tree.
-  bool IsFocusedWithinThisTree() const;
+  // Returns true if this node is focused in the current tree. Every
+  // accessibility tree may have its own independent focus, e.g. an iframe may
+  // have a different focus from the main web page.
+  bool IsFocusedInThisTree() const;
 
   // Returns true if an ancestor of this node (not including itself) is a
   // leaf node, meaning that this node is not actually exposed to any