Revert "[fuchsia][a11y] Refactors convert node ID logic."

This reverts commit c14fae86.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 811926 as the
culprit for failures in the build cycles as shown on:
https://analysis.chromium.org/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtL2MxNGZhZTg2Y2M0MzIyMDcyN2Q2NzNmYjJjMDRiNDJhZTI4YTI3NTQM

Sample Failed Build: https://ci.chromium.org/b/8867766288975154688

Sample Failed Step: compile

Original change's description:
> [fuchsia][a11y] Refactors convert node ID logic.
> 
> This change refactors the logic to convert an ax node ID to a fuchsia semantic node ID.
> 
> It also fixes the bug where if a regular ax node had ID == 0, it would conflict with the root ID.
> 
> R=yangsharon
> 
> TEST: web_engine_unittests
> Change-Id: Ie4ee52c65fbd5ad623986e015ad521e66c5e67fe
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2430264
> Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
> Reviewed-by: Sharon Yang <yangsharon@chromium.org>
> Commit-Queue: Lucas Radaelli <lucasradaelli@google.com>
> Cr-Commit-Position: refs/heads/master@{#811926}


Change-Id: Ide2c5fe9720fffc79de88a7b462906a4edc93d2c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2439702
Cr-Commit-Position: refs/heads/master@{#811934}

fuchsia/engine/browser/accessibility_bridge.cc

@@ -115,6 +115,17 @@ void AccessibilityBridge::OnCommitComplete() {
   TryCommit();
 }
 
+uint32_t AccessibilityBridge::ConvertToFuchsiaNodeId(int32_t ax_node_id) {
+  if (ax_node_id == root_id_) {
+    // On the Fuchsia side, the root node is indicated by id
+    // |kSemanticNodeRootId|, which is 0.
+    return kSemanticNodeRootId;
+  } else {
+    // AXNode ids are signed, Semantic Node ids are unsigned.
+    return bit_cast<uint32_t>(ax_node_id);
+  }
+}
+
 void AccessibilityBridge::AccessibilityEventReceived(
     const content::AXEventNotificationDetails& details) {
   // Updates to AXTree must be applied first.
@@ -132,7 +143,7 @@ void AccessibilityBridge::AccessibilityEventReceived(
         pending_hit_test_callbacks_.find(event.action_request_id) !=
             pending_hit_test_callbacks_.end()) {
       fuchsia::accessibility::semantics::Hit hit;
-      hit.set_node_id(ConvertToFuchsiaNodeId(event.id, root_id_));
+      hit.set_node_id(ConvertToFuchsiaNodeId(event.id));
 
       // Run the pending callback with the hit.
       pending_hit_test_callbacks_[event.action_request_id](std::move(hit));
@@ -217,7 +228,7 @@ void AccessibilityBridge::DeleteSubtree(ui::AXNode* node) {
   if (node->id() != root_id_) {
     to_send_.push_back(
         SemanticUpdateOrDelete(SemanticUpdateOrDelete::Type::DELETE, {},
-                               ConvertToFuchsiaNodeId(node->id(), root_id_)));
+                               ConvertToFuchsiaNodeId(node->id())));
   }
   for (ui::AXNode* child : node->children())
     DeleteSubtree(child);

fuchsia/engine/browser/accessibility_bridge.h

@@ -86,6 +86,10 @@ class WEB_ENGINE_EXPORT AccessibilityBridge
   // Callback for SemanticTree::CommitUpdates.
   void OnCommitComplete();
 
+  // Converts AXNode ids to Semantic Node ids, and handles special casing of
+  // the root.
+  uint32_t ConvertToFuchsiaNodeId(int32_t ax_node_id);
+
   // Deletes all nodes in subtree rooted at and including |node|, unless
   // |node| is the root of the tree. |tree| and |node| are owned by the
   // accessibility bridge.

fuchsia/engine/browser/ax_tree_converter.cc

@@ -8,11 +8,9 @@
 #include <fuchsia/ui/gfx/cpp/fidl.h>
 #include <fuchsia/ui/views/cpp/fidl.h>
 #include <lib/ui/scenic/cpp/commands.h>
-#include <stdint.h>
 #include <vector>
 
 #include "base/bit_cast.h"
-#include "base/numerics/safe_conversions.h"
 #include "ui/accessibility/ax_enums.mojom.h"
 #include "ui/accessibility/ax_tree_id.h"
 #include "ui/gfx/geometry/rect_f.h"
@@ -21,14 +19,6 @@ using fuchsia::accessibility::semantics::MAX_LABEL_SIZE;
 
 namespace {
 
-// Fuchsia's default root node ID.
-constexpr uint32_t kFuchsiaRootNodeId = 0;
-
-// Remmaped value for an AxNode ID that is 0 and is not a root.
-// Value is chosen specifically to be outside the range of a 32-bit signed int,
-// so as to not conflict with other values used by Chromium.
-constexpr uint32_t kZeroIdRemappedForFuchsia = 1u + INT32_MAX;
-
 fuchsia::accessibility::semantics::Role ConvertRole(ax::mojom::Role role) {
   if (role == ax::mojom::Role::kButton)
     return fuchsia::accessibility::semantics::Role::BUTTON;
@@ -137,7 +127,7 @@ std::vector<uint32_t> ConvertChildIds(std::vector<int32_t> ids) {
   std::vector<uint32_t> child_ids;
   child_ids.reserve(ids.size());
   for (auto i : ids) {
-    child_ids.push_back(base::checked_cast<uint32_t>(i));
+    child_ids.push_back(bit_cast<uint32_t>(i));
   }
   return child_ids;
 }
@@ -167,7 +157,7 @@ fuchsia::ui::gfx::mat4 ConvertTransform(gfx::Transform* transform) {
 fuchsia::accessibility::semantics::Node AXNodeDataToSemanticNode(
     const ui::AXNodeData& node) {
   fuchsia::accessibility::semantics::Node fuchsia_node;
-  fuchsia_node.set_node_id(base::checked_cast<uint32_t>(node.id));
+  fuchsia_node.set_node_id(bit_cast<uint32_t>(node.id));
   fuchsia_node.set_role(ConvertRole(node.role));
   fuchsia_node.set_states(ConvertStates(node));
   fuchsia_node.set_attributes(ConvertAttributes(node));
@@ -202,16 +192,3 @@ bool ConvertAction(fuchsia::accessibility::semantics::Action fuchsia_action,
       return false;
   }
 }
-
-uint32_t ConvertToFuchsiaNodeId(int32_t ax_node_id, int32_t ax_root_node_id) {
-  if (ax_node_id == ax_root_node_id)
-    return kFuchsiaRootNodeId;
-
-  if (ax_node_id == kFuchsiaRootNodeId) {
-    // This AxNode is not the root, but its ID is the same as Fuchsia's root ID.
-    // We remap it to something different to not create a confflict.
-    return kZeroIdRemappedForFuchsia;
-  }
-
-  return base::checked_cast<uint32_t>(ax_node_id);
-}

fuchsia/engine/browser/ax_tree_converter.h

@@ -24,12 +24,4 @@ AXNodeDataToSemanticNode(const ui::AXNodeData& node);
 bool ConvertAction(fuchsia::accessibility::semantics::Action fuchsia_action,
                    ax::mojom::Action* mojom_action);
 
-// Converts |ax_node_id|, which is signed, to a Fuchsia node ID, which is
-// unsigned.
-// Fuchsia requires root node IDs to be zero. This function ensures
-// that the conversion takes that into account.
-// If |ax_node_id| is 0 and is not the root, we return the
-// MAX(int32_t) + 1, which is a number that will never conflict with other IDs.
-uint32_t ConvertToFuchsiaNodeId(int32_t ax_node_id, int32_t ax_root_node_id);
-
 #endif  // FUCHSIA_ENGINE_BROWSER_AX_TREE_CONVERTER_H_

fuchsia/engine/browser/ax_tree_converter_unittest.cc

@@ -41,9 +41,6 @@ ui::AXNodeData CreateAXNodeData(ax::mojom::Role role,
                                 base::StringPiece description,
                                 ax::mojom::CheckedState checked_state) {
   ui::AXNodeData node;
-  // Important! ID must be set to zero here because its default value (-1), will
-  // fail when getting converted to an unsigned int (Fuchsia's ID format).
-  node.id = 0;
   node.role = role;
   node.AddAction(action);
   node.AddIntAttribute(ax::mojom::IntAttribute::kCheckedState,
@@ -116,9 +113,8 @@ TEST_F(AXTreeConverterTest, AllFieldsSetAndEqual) {
   states.set_hidden(false);
   states.set_selected(false);
   auto expected_node = CreateSemanticNode(
-      static_cast<uint32_t>(source_node_data.id), Role::BUTTON,
-      std::move(attributes), std::move(states),
-      std::vector<Action>{Action::SET_FOCUS},
+      source_node_data.id, Role::BUTTON, std::move(attributes),
+      std::move(states), std::vector<Action>{Action::SET_FOCUS},
       std::vector<uint32_t>{kChildId1, kChildId2, kChildId3}, box, mat.value);
 
   EXPECT_TRUE(fidl::Equals(converted_node, expected_node));
@@ -126,7 +122,6 @@ TEST_F(AXTreeConverterTest, AllFieldsSetAndEqual) {
 
 TEST_F(AXTreeConverterTest, SomeFieldsSetAndEqual) {
   ui::AXNodeData source_node_data;
-  source_node_data.id = 0;
   source_node_data.AddAction(ax::mojom::Action::kFocus);
   source_node_data.AddAction(ax::mojom::Action::kSetValue);
   source_node_data.child_ids = std::vector<int32_t>{kChildId1};
@@ -138,11 +133,10 @@ TEST_F(AXTreeConverterTest, SomeFieldsSetAndEqual) {
             converted_node.node_id());
 
   Node expected_node;
-  expected_node.set_node_id(static_cast<uint32_t>(source_node_data.id));
+  expected_node.set_node_id(source_node_data.id);
   expected_node.set_actions(
       std::vector<Action>{Action::SET_FOCUS, Action::SET_VALUE});
-  expected_node.set_child_ids(
-      std::vector<uint32_t>{static_cast<uint32_t>(kChildId1)});
+  expected_node.set_child_ids(std::vector<uint32_t>{kChildId1});
   expected_node.set_role(Role::IMAGE);
   States states;
   states.set_hidden(false);
@@ -204,19 +198,4 @@ TEST_F(AXTreeConverterTest, FieldMismatch) {
   EXPECT_FALSE(fidl::Equals(converted_node, expected_node));
 }
 
-TEST_F(AXTreeConverterTest, ConvertToFuchsiaNodeId) {
-  // Root AxNode is 0, Fuchsia is also 0.
-  EXPECT_EQ(0u, ConvertToFuchsiaNodeId(0, 0));
-
-  // Root AxNode is not 0, Fuchsia is still 0.
-  EXPECT_EQ(0u, ConvertToFuchsiaNodeId(2, 2));
-
-  // Regular AxNode is 0, Fuchsia can't be 0.
-  EXPECT_EQ(static_cast<uint32_t>(std::numeric_limits<int32_t>::max()) + 1,
-            ConvertToFuchsiaNodeId(0, 2));
-
-  // Regular AxNode is not 0, Fuchsia is same value.
-  EXPECT_EQ(10u, ConvertToFuchsiaNodeId(10, 0));
-}
-
 }  // namespace