Add missing NULL checks to NativeViewAccessibilityWin.

ui/views/accessibility/native_view_accessibility_win.cc

 // Copyright (c) 2012 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 "ui/views/accessibility/native_view_accessibility_win.h"
 
 #include <oleacc.h>
 #include <UIAutomationClient.h>
 
 #include <set>
@@ skipping 772 matching lines @@
   return E_NOTIMPL;
 }
 
 STDMETHODIMP NativeViewAccessibilityWin::accSelect(
     LONG flagsSelect, VARIANT var_id) {
   return E_NOTIMPL;
 }
 
 STDMETHODIMP NativeViewAccessibilityWin::get_accHelp(
     VARIANT var_id, BSTR* help) {
+  if (!IsValidId(var_id) || !help)
+    return E_INVALIDARG;
+
+  if (!view_)
+    return E_FAIL;
+
   base::string16 temp = base::UTF8ToUTF16(view_->GetClassName());
   *help = SysAllocString(temp.c_str());
   return S_OK;
 }
 
 STDMETHODIMP NativeViewAccessibilityWin::get_accHelpTopic(
     BSTR* help_file, VARIANT var_id, LONG* topic_id) {
   if (help_file) {
     *help_file = NULL;
   }
@@ skipping 373 matching lines @@
       base::win::GetVersion() >= base::win::VERSION_WIN8) {
     return QueryInterface(riid, object);
   }
 
   *object = NULL;
   return E_FAIL;
 }
 
 STDMETHODIMP NativeViewAccessibilityWin::GetPatternProvider(
     PATTERNID id, IUnknown** provider) {
+  if (!view_)
+    return E_FAIL;
+
+  if (!provider)
+    return E_INVALIDARG;
+
   DVLOG(1) << "In Function: "
            << __FUNCTION__
            << " for pattern id: "
            << id;
   if (id == UIA_ValuePatternId || id == UIA_TextPatternId) {
     ui::AXViewState state;
     view_->GetAccessibleState(&state);
     long role = MSAARole(state.role);
 
     if (role == ROLE_SYSTEM_TEXT) {
       DVLOG(1) << "Returning UIA text provider";
       base::win::UIATextProvider::CreateTextProvider(
           state.value, true, provider);
       return S_OK;
     }
   }
   return E_NOTIMPL;
 }
 
 STDMETHODIMP NativeViewAccessibilityWin::GetPropertyValue(PROPERTYID id,
                                                           VARIANT* ret) {
+  if (!view_)
+    return E_FAIL;
+
+  if (!ret)
+    return E_INVALIDARG;
+
   DVLOG(1) << "In Function: "
            << __FUNCTION__
            << " for property id: "
            << id;
   if (id == UIA_ControlTypePropertyId) {
     ui::AXViewState state;
     view_->GetAccessibleState(&state);
     long role = MSAARole(state.role);
     if (role == ROLE_SYSTEM_TEXT) {
       V_VT(ret) = VT_I4;
@@ skipping 314 matching lines @@
     if (view == NULL || view == view_) {
       alert_target_view_storage_ids_.erase(
           alert_target_view_storage_ids_.begin() + i);
     } else {
       ++i;
     }
   }
 }
 
 }  // namespace views