Add an option to AXEventGenerator to always fire load complete

R=dmazzoni@chromium.org

Fixed: 927697
Change-Id: If7e8aa4898d44b38f9b2df7cdca7a2aed7c16063
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210820
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771297}

extensions/renderer/api/automation/automation_ax_tree_wrapper.cc

@@ -248,6 +248,7 @@ AutomationAXTreeWrapper::AutomationAXTreeWrapper(
     : tree_id_(tree_id), owner_(owner), event_generator_(&tree_) {
   tree_.AddObserver(this);
   ui::AXTreeManagerMap::GetInstance().AddTreeManager(tree_id, this);
+  event_generator_.set_always_fire_load_complete(true);
 }
 
 AutomationAXTreeWrapper::~AutomationAXTreeWrapper() {

ui/accessibility/ax_event_generator.cc

@@ -616,6 +616,9 @@ void AXEventGenerator::FireRelationSourceEvents(AXTree* tree,
 // Attempts to suppress load-related events that we presume no AT will be
 // interested in under any circumstances, such as pages which have no size.
 bool AXEventGenerator::ShouldFireLoadEvents(AXNode* node) {
+  if (always_fire_load_complete_)
+    return true;
+
   const AXNodeData& data = node->data();
   return data.relative_bounds.bounds.width() ||
          data.relative_bounds.bounds.height();

ui/accessibility/ax_event_generator.h

@@ -170,6 +170,10 @@ class AX_EXPORT AXEventGenerator : public AXTreeObserver {
   // same order they were added.
   void AddEvent(ui::AXNode* node, Event event);
 
+  void set_always_fire_load_complete(bool val) {
+    always_fire_load_complete_ = val;
+  }
+
  protected:
   // AXTreeObserver overrides.
   void OnNodeDataChanged(AXTree* tree,
@@ -241,6 +245,8 @@ class AX_EXPORT AXEventGenerator : public AXTreeObserver {
   // OnAtomicUpdateFinished. List of nodes whose active descendant changed.
   std::vector<AXNode*> active_descendant_changed_;
 
+  bool always_fire_load_complete_ = false;
+
   // Please make sure that this ScopedObserver is always declared last in order
   // to prevent any use-after-free.
   ScopedObserver<AXTree, AXTreeObserver> tree_event_observer_{this};