[inspector] deduplicate stack frames

src/inspector/v8-debugger.h

Index: src/inspector/v8-debugger.h
diff --git a/src/inspector/v8-debugger.h b/src/inspector/v8-debugger.h
index f49d2088394e313c57da63fe54fa8f698c69ec34..ed9275395bc1eab9f664dd7e38e10dced2f70da4 100644
--- a/src/inspector/v8-debugger.h
+++ b/src/inspector/v8-debugger.h
@@ -23,6 +23,7 @@ namespace v8_inspector {
 
 class AsyncStackTrace;
 struct ScriptBreakpoint;
+class StackFrame;
 class V8Debugger;
 class V8DebuggerAgentImpl;
 class V8InspectorImpl;
@@ -85,6 +86,9 @@ class V8Debugger : public v8::debug::DebugDelegate {
   std::shared_ptr<AsyncStackTrace> currentAsyncParent();
   std::shared_ptr<AsyncStackTrace> currentAsyncCreation();
 
+  std::shared_ptr<StackFrame> lookupFrame(int frameId);
+  void storeFrame(int frameId, std::shared_ptr<StackFrame> frame);
+
   std::unique_ptr<V8StackTraceImpl> createStackTrace(v8::Local<v8::StackTrace>);
   std::unique_ptr<V8StackTraceImpl> captureStackTrace(bool fullStack);
 
@@ -201,6 +205,7 @@ class V8Debugger : public v8::debug::DebugDelegate {
   // V8Debugger owns all the async stacks, while most of the other references
   // are weak, which allows to collect some stacks when there are too many.
   std::list<std::shared_ptr<AsyncStackTrace>> m_allAsyncStacks;
+  std::map<int, std::weak_ptr<StackFrame>> m_framesCache;
 
   protocol::HashMap<V8DebuggerAgentImpl*, int> m_maxAsyncCallStackDepthMap;
   void* m_taskWithScheduledBreak = nullptr;