Better handle null delegates by returning instead of CHECK()

content/browser/accessibility/browser_accessibility_com_win.cc

 // Copyright (c) 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/accessibility/browser_accessibility_com_win.h"
 
 #include <UIAutomationClient.h>
 #include <UIAutomationCoreApi.h>
 
 #include <algorithm>
@@ skipping 3032 matching lines @@
 //
 
 // static
 HRESULT WINAPI BrowserAccessibilityComWin::InternalQueryInterface(
     void* this_ptr,
     const _ATL_INTMAP_ENTRY* entries,
     REFIID iid,
     void** object) {
   BrowserAccessibilityComWin* accessibility =
       reinterpret_cast<BrowserAccessibilityComWin*>(this_ptr);
+
+  if (!accessibility->owner()) {
+    *object = nullptr;
+    return E_NOINTERFACE;
+  }
+
   int32_t ia_role = accessibility->MSAARole();
   if (iid == IID_IAccessibleImage) {
     if (ia_role != ROLE_SYSTEM_GRAPHIC) {
-      *object = NULL;
+      *object = nullptr;
       return E_NOINTERFACE;
     }
   } else if (iid == IID_IAccessibleTable || iid == IID_IAccessibleTable2) {
     if (ia_role != ROLE_SYSTEM_TABLE) {
-      *object = NULL;
+      *object = nullptr;
       return E_NOINTERFACE;
     }
   } else if (iid == IID_IAccessibleTableCell) {
     if (!ui::IsCellOrTableHeaderRole(accessibility->owner()->GetRole())) {
-      *object = NULL;
+      *object = nullptr;
       return E_NOINTERFACE;
     }
   } else if (iid == IID_IAccessibleValue) {
     if (!accessibility->IsRangeValueSupported()) {
-      *object = NULL;
+      *object = nullptr;
       return E_NOINTERFACE;
     }
   } else if (iid == IID_ISimpleDOMDocument) {
     if (ia_role != ROLE_SYSTEM_DOCUMENT) {
-      *object = NULL;
+      *object = nullptr;
       return E_NOINTERFACE;
     }
   } else if (iid == IID_IAccessibleHyperlink) {
     auto* ax_object =
         reinterpret_cast<const BrowserAccessibilityComWin*>(this_ptr);
     if (!ax_object || !ax_object->IsHyperlink()) {
       *object = nullptr;
       return E_NOINTERFACE;
     }
   }
@@ skipping 1490 matching lines @@
 
 BrowserAccessibilityComWin* ToBrowserAccessibilityComWin(
     BrowserAccessibility* obj) {
   if (!obj || !obj->IsNative())
     return nullptr;
   auto* result = static_cast<BrowserAccessibilityWin*>(obj)->GetCOM();
   return result;
 }
 
 }  // namespace content