Avoid Context::Enter and Context::Exit if we're reentering the active and last entered context

src/api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 164 matching lines @@
   explicit CallDepthScope(i::Isolate* isolate, Local<Context> context,
                           bool do_callback)
       : isolate_(isolate),
         context_(context),
         escaped_(false),
         do_callback_(do_callback) {
     // TODO(dcarney): remove this when blink stops crashing.
     DCHECK(!isolate_->external_caught_exception());
     isolate_->IncrementJsCallsFromApiCounter();
     isolate_->handle_scope_implementer()->IncrementCallDepth();
-    if (!context_.IsEmpty()) context_->Enter();
+    if (!context.IsEmpty()) {
+      i::Handle<i::Context> env = Utils::OpenHandle(*context);
+      i::HandleScopeImplementer* impl = isolate->handle_scope_implementer();
+      if (isolate->context() != nullptr &&
+          isolate->context()->native_context() == env->native_context() &&
+          impl->LastEnteredContextWas(env)) {
+        context_ = Local<Context>();
+      } else {
+        context_->Enter();
+      }
+    }
     if (do_callback_) isolate_->FireBeforeCallEnteredCallback();
   }
   ~CallDepthScope() {
     if (!context_.IsEmpty()) context_->Exit();
     if (!escaped_) isolate_->handle_scope_implementer()->DecrementCallDepth();
     if (do_callback_) isolate_->FireCallCompletedCallback();
 #ifdef DEBUG
     if (do_callback_) CheckMicrotasksScopesConsistency(isolate_);
 #endif
   }
@@ skipping 8743 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8