Bug 1198336 - P3: Implement AXLiveRegionSearchKey. r=morgan

I think VoiceOver uses this to pull in all live regions so it
can check for deletions when they change later on.

Depends on D96292

Differential Revision: https://phabricator.services.mozilla.com/D96293

accessible/mac/MOXSearchInfo.mm

@@ -329,6 +329,13 @@ using namespace mozilla::a11y;
               : RotorMacRoleRule(@"AXTextField");
       [matches addObjectsFromArray:[self getMatchesForRule:rule]];
     }
+
+    if ([key isEqualToString:@"AXLiveRegionSearchKey"]) {
+      RotorLiveRegionRule rule = mImmediateDescendantsOnly
+                                     ? RotorLiveRegionRule(geckoRootAcc)
+                                     : RotorLiveRegionRule();
+      [matches addObjectsFromArray:[self getMatchesForRule:rule]];
+    }
   }
 
   return matches;

accessible/mac/RotorRules.h

@@ -113,6 +113,15 @@ class RotorHeadingLevelRule : public RotorRoleRule {
   int32_t mLevel;
 };
 
+class RotorLiveRegionRule : public RotorRule {
+ public:
+  explicit RotorLiveRegionRule(AccessibleOrProxy& aDirectDescendantsFrom)
+      : RotorRule(aDirectDescendantsFrom) {}
+  explicit RotorLiveRegionRule() : RotorRule() {}
+
+  uint16_t Match(const AccessibleOrProxy& aAccOrProxy) override;
+};
+
 /**
  * This rule matches all accessibles with roles::OUTLINEITEM. If
  * outlines are nested, it ignores the nested subtree and returns

accessible/mac/RotorRules.mm

@@ -308,6 +308,18 @@ uint16_t RotorHeadingLevelRule::Match(const AccessibleOrProxy& aAccOrProxy) {
   return result;
 }
 
+uint16_t RotorLiveRegionRule::Match(const AccessibleOrProxy& aAccOrProxy) {
+  uint16_t result = RotorRule::Match(aAccOrProxy);
+
+  if ((result & nsIAccessibleTraversalRule::FILTER_MATCH)) {
+    mozAccessible* nativeMatch = GetNativeFromGeckoAccessible(aAccOrProxy);
+    if (![nativeMatch moxIsLiveRegion]) {
+      result &= ~nsIAccessibleTraversalRule::FILTER_MATCH;
+    }
+  }
+  return result;
+}
+
 // Outline Rule
 
 OutlineRule::OutlineRule() : RotorRule(){};

accessible/tests/browser/mac/browser_live_regions.js

@@ -99,22 +99,22 @@ addAccessibleTask(
         <div id="status" role="status"></div>
         <output id="output"></output>`;
     });
-    await loadComplete;
+    let webArea = (await loadComplete)[0];
 
-    liveRegionRemoved = waitForEvent(EVENT_LIVE_REGION_REMOVED, "status");
-    await SpecialPowers.spawn(browser, [], () => {
-      content.document
-        .getElementById("status")
-        .setAttribute("aria-live", "off");
-    });
-    await liveRegionRemoved;
-
-    liveRegionRemoved = waitForEvent(EVENT_LIVE_REGION_REMOVED, "output");
-    await SpecialPowers.spawn(browser, [], () => {
-      content.document
-        .getElementById("output")
-        .setAttribute("aria-live", "off");
-    });
-    await liveRegionRemoved;
+    is(webArea.getAttributeValue("AXRole"), "AXWebArea", "web area yeah");
+    const searchPred = {
+      AXSearchKey: "AXLiveRegionSearchKey",
+      AXResultsLimit: -1,
+      AXDirection: "AXDirectionNext",
+    };
+    const liveRegions = webArea.getParameterizedAttributeValue(
+      "AXUIElementsForSearchPredicate",
+      NSDictionary(searchPred)
+    );
+    Assert.deepEqual(
+      liveRegions.map(r => r.getAttributeValue("AXDOMIdentifier")),
+      ["region-1", "region-2", "status", "output"],
+      "SearchPredicate returned all live regions"
+    );
   }
 );