Use StringBuilder::appendLiteral() / StringBuilder::append(char) when possible

Source/core/inspector/InspectorInspectorAgent.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Matt Lilek <webkit@mattlilek.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 69 matching lines @@
     if (m_injectedScriptForOrigin.isEmpty())
         return;
 
     String origin = frame->document()->securityOrigin()->toRawString();
     String script = m_injectedScriptForOrigin.get(origin);
     if (script.isEmpty())
         return;
     int injectedScriptId = m_injectedScriptManager->injectedScriptIdFor(ScriptState::forMainWorld(frame));
     StringBuilder scriptSource;
     scriptSource.append(script);
-    scriptSource.append("(");
+    scriptSource.append('(');
     scriptSource.appendNumber(injectedScriptId);
-    scriptSource.append(")");
+    scriptSource.append(')');
     frame->script().executeScriptInMainWorld(scriptSource.toString());
 }
 
 void InspectorInspectorAgent::init()
 {
     m_instrumentingAgents->setInspectorInspectorAgent(this);
 }
 
 void InspectorInspectorAgent::setFrontend(InspectorFrontend* inspectorFrontend)
 {
@@ skipping 60 matching lines @@
         m_frontend->inspect(objectToInspect, hints);
         m_pendingInspectData.first = nullptr;
         m_pendingInspectData.second = nullptr;
         return;
     }
     m_pendingInspectData.first = objectToInspect;
     m_pendingInspectData.second = hints;
 }
 
 } // namespace blink