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

Source/core/inspector/InspectorDebuggerAgent.cpp

Index: Source/core/inspector/InspectorDebuggerAgent.cpp
diff --git a/Source/core/inspector/InspectorDebuggerAgent.cpp b/Source/core/inspector/InspectorDebuggerAgent.cpp
index adf92f72854e066d2fe36f075bcc67cafcfb982e..545d597f764e3bd83c3a3e447599db9d3abba3b3 100644
--- a/Source/core/inspector/InspectorDebuggerAgent.cpp
+++ b/Source/core/inspector/InspectorDebuggerAgent.cpp
@@ -188,17 +188,20 @@ bool InspectorDebuggerAgent::checkEnabled(ErrorString* errorString)
     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()
@@ -225,12 +228,15 @@ 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());
 }