DevTools: do not enable debugger for pages where script execution is prohibited

Source/core/inspector/InspectorDebuggerAgent.cpp

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 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
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 170 matching lines @@
 }
 
 bool InspectorDebuggerAgent::checkEnabled(ErrorString* errorString)
 {
     if (enabled())
         return true;
     *errorString = "Debugger agent is not enabled";
     return false;
 }
 
-void InspectorDebuggerAgent::enable()
+bool InspectorDebuggerAgent::enable()
 {
+    if (!startListeningScriptDebugServer())
+        return false;
+
     m_instrumentingAgents->setInspectorDebuggerAgent(this);
 
-    startListeningScriptDebugServer();
     // FIXME(WK44513): breakpoints activated flag should be synchronized between all front-ends
     scriptDebugServer().setBreakpointsActivated(true);
 
     m_state->setBoolean(DebuggerAgentState::debuggerEnabled, true);
     if (m_listener)
         m_listener->debuggerWasEnabled();
+    return true;
 }
 
 void InspectorDebuggerAgent::disable()
 {
     m_state->setObject(DebuggerAgentState::javaScriptBreakpoints, JSONObject::create());
     m_state->setLong(DebuggerAgentState::pauseOnExceptionsState, ScriptDebugServer::DontPauseOnExceptions);
     m_state->setString(DebuggerAgentState::skipStackPattern, "");
     m_state->setBoolean(DebuggerAgentState::skipContentScripts, false);
     m_state->setLong(DebuggerAgentState::asyncCallStackDepth, 0);
     m_state->setBoolean(DebuggerAgentState::promiseTrackerEnabled, false);
     m_instrumentingAgents->setInspectorDebuggerAgent(0);
 
     stopListeningScriptDebugServer();
     clear();
 
     if (m_listener)
         m_listener->debuggerWasDisabled();
 
     m_skipAllPauses = false;
 }
 
 bool InspectorDebuggerAgent::enabled()
 {
     return m_state->getBoolean(DebuggerAgentState::debuggerEnabled);
 }
 
-void InspectorDebuggerAgent::enable(ErrorString*)
+void InspectorDebuggerAgent::enable(ErrorString* errorString)
 {
     if (enabled())
         return;
 
-    enable();
+    if (!enable()) {
+        *errorString = "Failed to enable debugger";
+        return;
+    }
 
     ASSERT(frontend());
 }
 
 void InspectorDebuggerAgent::disable(ErrorString*)
 {
     if (!enabled())
         return;
 
     disable();
@@ skipping 1436 matching lines @@
     visitor->trace(m_v8AsyncCallTracker);
     visitor->trace(m_promiseTracker);
     visitor->trace(m_asyncOperations);
     visitor->trace(m_currentAsyncCallChain);
     visitor->trace(m_asyncCallTrackingListeners);
 #endif
     InspectorBaseAgent::trace(visitor);
 }
 
 } // namespace blink