Fix build with disabled accessibility

Change-Id: Icdf58c228fc2511508c997e733d881d53709dd21
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

src/core/accessibility_tree_formatter_qt.cpp

@@ -52,6 +52,7 @@
 
 namespace content {
 
+#ifndef QT_NO_ACCESSIBILITY
 class AccessibilityTreeFormatterQt : public AccessibilityTreeFormatterBrowser {
 public:
     explicit AccessibilityTreeFormatterQt();
@@ -66,12 +67,6 @@ private:
     base::string16 ProcessTreeForOutput(const base::DictionaryValue &node, base::DictionaryValue * = nullptr) override;
 };
 
-// static
-AccessibilityTreeFormatter* AccessibilityTreeFormatter::Create()
-{
-    return new AccessibilityTreeFormatterQt();
-}
-
 AccessibilityTreeFormatterQt::AccessibilityTreeFormatterQt()
 {
 }
@@ -203,4 +198,16 @@ const std::string AccessibilityTreeFormatterQt::GetDenyString()
     return "@QT-DENY:";
 }
 
+#endif // QT_NO_ACCESSIBILITY
+
+// static
+AccessibilityTreeFormatter* AccessibilityTreeFormatter::Create()
+{
+#ifndef QT_NO_ACCESSIBILITY
+    return new AccessibilityTreeFormatterQt();
+#else
+    return nullptr;
+#endif
 }
+
+} // namespace content

src/core/browser_accessibility_qt.h

@@ -41,9 +41,10 @@
 #define BROWSER_ACCESSIBILITY_QT_H
 
 #include <QtGui/qaccessible.h>
-#ifndef QT_NO_ACCESSIBILITY
 #include "content/browser/accessibility/browser_accessibility.h"
 
+#ifndef QT_NO_ACCESSIBILITY
+
 namespace content {
 
 class BrowserAccessibilityQt