[DevTools] Allow modifying instrumenting agents while iterating.

third_party/WebKit/Source/core/inspector/CodeGeneratorInstrumentation.py

Index: third_party/WebKit/Source/core/inspector/CodeGeneratorInstrumentation.py
diff --git a/third_party/WebKit/Source/core/inspector/CodeGeneratorInstrumentation.py b/third_party/WebKit/Source/core/inspector/CodeGeneratorInstrumentation.py
index 188ed26e4f4e261ac542214bb38c4711d84835e5..eaf7a609b7099a4573fddfc91f8d76a2be737590 100755
--- a/third_party/WebKit/Source/core/inspector/CodeGeneratorInstrumentation.py
+++ b/third_party/WebKit/Source/core/inspector/CodeGeneratorInstrumentation.py
@@ -102,6 +102,72 @@ class CORE_EXPORT InstrumentingAgents : public GarbageCollected<InstrumentingAge
 public:
     InstrumentingAgents();
     DECLARE_TRACE();
+
+    template <class T>
+    class AgentsList {
+        DISALLOW_NEW();
+    private:
+        using AgentsVector = HeapVector<Member<T>>;
+        using InnerIterator = typename AgentsVector::iterator;
+
+    public:
+        class Iterator {
+            STACK_ALLOCATED();
+        public:
+            Iterator operator++(int) { InnerIterator value = m_value; ++*this; return Iterator(value, m_list); }
+            Iterator& operator++() { if (!isEnd()) ++m_value; return *this; }
+            bool operator==(const Iterator& other) const { return (isEnd() && other.isEnd()) || m_value == other.m_value; }
+            bool operator!=(const Iterator& other) const { return !(*this == other); }
+            T* operator*() { return *m_value; }
+            T* operator->() { return *m_value; }
+
+        private:
+            friend class AgentsList;
+            Iterator(InnerIterator value, AgentsList* list) : m_value(value), m_list(list), m_version(m_list->m_version) { }
+            bool isEnd() const { return m_list->m_version != m_version || m_value == m_list->m_vector.end(); }
+
+            InnerIterator m_value;
+            Member<AgentsList> m_list;
+            int m_version;
+        };
+
+        Iterator begin() { return Iterator(m_vector.begin(), this); }
+        Iterator end() { return Iterator(m_vector.end(), this); }
+
+        DEFINE_INLINE_TRACE()
+        {
+            visitor->trace(m_vector);
+        }
+
+    private:
+        friend class InstrumentingAgents;
+        friend class Iterator;
+
+        AgentsList() : m_version(0) { }
+
+        bool isEmpty() const { return m_vector.isEmpty(); }
+
+        void add(T* value)
+        {
+            if (m_vector.contains(value))
+                return;
+            ++m_version;
+            m_vector.append(value);
+        }
+
+        void remove(T* value)
+        {
+            size_t index = m_vector.find(value);
+            if (index == WTF::kNotFound)
+                return;
+            ++m_version;
+            m_vector.remove(index);
+        }
+
+        AgentsVector m_vector;
+        int m_version;
+    };
+
 ${accessor_list}
 
 private:
@@ -115,7 +181,7 @@ ${member_list}
 
 template_instrumenting_agent_accessor = string.Template("""
     bool has${class_name}s() const { return ${has_member_name}; }
-    const HeapHashSet<Member<${class_name}>>& ${getter_name}s() const { return ${member_name}; }
+    AgentsList<${class_name}>& ${getter_name}s() { return ${member_name}; }
     void add${class_name}(${class_name}* agent);
     void remove${class_name}(${class_name}* agent);""")
 
@@ -123,7 +189,7 @@ template_instrumenting_agent_impl = string.Template("""
 void InstrumentingAgents::add${class_name}(${class_name}* agent)
 {
     ${member_name}.add(agent);
-    ${has_member_name} = true;
+    ${has_member_name} = !${member_name}.isEmpty();
 }
 
 void InstrumentingAgents::remove${class_name}(${class_name}* agent)
@@ -389,7 +455,7 @@ def generate_instrumenting_agents(used_agents):
             getter_name=getter_name,
             member_name=member_name,
             has_member_name=has_member_name))
-        member_list.append("    HeapHashSet<Member<%s>> %s;" % (class_name, member_name))
+        member_list.append("    AgentsList<%s> %s;" % (class_name, member_name))
         member_list.append("    bool %s;" % has_member_name)
         init_list.append("%s(false)" % has_member_name)
         trace_list.append("visitor->trace(%s);" % member_name)