Avoid using declarations in headers which introduce symbol conflicts.

third_party/WebKit/Source/modules/accessibility/InspectorAccessibilityAgent.cpp

 // Copyright 2014 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 "modules/accessibility/InspectorAccessibilityAgent.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/DOMNodeIds.h"
 #include "core/dom/Element.h"
@@ skipping 16 matching lines @@
 using protocol::Accessibility::AXNode;
 using protocol::Accessibility::AXNodeId;
 using protocol::Accessibility::AXProperty;
 using protocol::Accessibility::AXValueSource;
 using protocol::Accessibility::AXValueType;
 using protocol::Accessibility::AXRelatedNode;
 using protocol::Accessibility::AXRelationshipAttributes;
 using protocol::Accessibility::AXValue;
 using protocol::Accessibility::AXWidgetAttributes;
 using protocol::Accessibility::AXWidgetStates;
+using protocol::Maybe;
+using protocol::Response;
 
 using namespace HTMLNames;
 
 namespace {
 
 static const AXID kIDForInspectedNodeWithNoAXNode = 0;
 
 void fillLiveRegionProperties(AXObject& axObject,
                               protocol::Array<AXProperty>& properties) {
   if (!axObject.liveRegionRoot())
@@ skipping 683 matching lines @@
   }
 }
 
 DEFINE_TRACE(InspectorAccessibilityAgent) {
   visitor->trace(m_page);
   visitor->trace(m_domAgent);
   InspectorBaseAgent::trace(visitor);
 }
 
 }  // namespace blink