Bug 1417327 part 3: Accessible handler: Fix cache for IAccessible::ac…

…cDefaultAction and use it for IAccessibleAction::name(0). r=MarcoZ

1. Bug 1363595 added support for retrieving accDefaultAction from the cache, but the value was never cached in the first place.
This would have meant that accDefaultAction was returning nothing to clients.

2. Since accDefaultAction is the name of the first action, we can also use this cached value for IAccessibleAction::name for index 0.

MozReview-Commit-ID: 6PGRH45kKdB

--HG--
extra : rebase_source : 52688f1e44ad7613c5dd14903b6240a51aa2d4eb

accessible/ipc/win/HandlerProvider.cpp

@@ -315,6 +315,11 @@ HandlerProvider::BuildDynamicIA2Data(DynamicIA2Data* aOutIA2Data)
     return;
   }
 
+  hr = target->get_accDefaultAction(kChildIdSelf, &aOutIA2Data->mDefaultAction);
+  if (FAILED(hr)) {
+    return;
+  }
+
   hr = target->get_accChildCount(&aOutIA2Data->mChildCount);
   if (FAILED(hr)) {
     return;

accessible/ipc/win/handler/AccessibleHandler.cpp

@@ -1280,6 +1280,24 @@ AccessibleHandler::get_keyBinding(long actionIndex,
 HRESULT
 AccessibleHandler::get_name(long actionIndex, BSTR* name)
 {
+  if (!name) {
+    return E_INVALIDARG;
+  }
+
+  if (HasPayload()) {
+    if (actionIndex >= mCachedData.mDynamicData.mNActions) {
+      // Action does not exist.
+      return E_INVALIDARG;
+    }
+
+    if (actionIndex == 0) {
+      // same as accDefaultAction.
+      GET_BSTR(mDefaultAction, *name);
+      return S_OK;
+    }
+  }
+
+  // At this point, there's either no payload or actionIndex is > 0.
   HRESULT hr = ResolveIAHyperlink();
   if (FAILED(hr)) {
     return hr;