Fix support for accessible action verbs and performing the default action.

content/browser/accessibility/browser_accessibility_win.cc

Index: content/browser/accessibility/browser_accessibility_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index bf3b0affdd751d7d45d1dc592723149d05660882..cb86cd1c568b2c7b571997c2f6b5ea79f8877ebd 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -231,6 +231,10 @@ HRESULT BrowserAccessibilityWin::accDoDefaultAction(VARIANT var_id) {
   if (!target)
     return E_INVALIDARG;
 
+  // Return an error if it's not clickable.
+  if (!target->HasStringAttribute(ui::AX_ATTR_ACTION))
+    return DISP_E_MEMBERNOTFOUND;
+
   manager()->DoDefaultAction(*target);
   return S_OK;
 }