[wasm] prototype for breakpoint support.

src/debug/debug-scopes.cc

 // Copyright 2015 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/debug/debug-scopes.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/debug/debug.h"
 #include "src/frames-inl.h"
@@ skipping 40 matching lines @@
   // and include nested scopes into the "fast" iteration case as well.
   bool ignore_nested_scopes = (option == IGNORE_NESTED_SCOPES);
   bool collect_non_locals = (option == COLLECT_NON_LOCALS);
   if (!ignore_nested_scopes && shared_info->HasDebugInfo()) {
     // The source position at return is always the end of the function,
     // which is not consistent with the current scope chain. Therefore all
     // nested with, catch and block contexts are skipped, and we can only
     // inspect the function scope.
     // This can only happen if we set a break point inside right before the
     // return, which requires a debug info to be available.
-    Handle<DebugInfo> debug_info(shared_info->GetDebugInfo());
 
     // Find the break point where execution has stopped.
-    BreakLocation location = BreakLocation::FromFrame(debug_info, GetFrame());
+    BreakLocation location = BreakLocation::FromFrame(GetFrame());
 
     ignore_nested_scopes = location.IsReturn();
   }
 
   if (ignore_nested_scopes) {
     if (scope_info->HasContext()) {
       context_ = Handle<Context>(context_->declaration_context(), isolate_);
     } else {
       while (context_->closure() == *function) {
         context_ = Handle<Context>(context_->previous(), isolate_);
@@ skipping 728 matching lines @@
     DCHECK((beg_pos >= 0 && end_pos >= 0) || inner_scope->is_hidden());
     if (beg_pos <= position && position < end_pos) {
       GetNestedScopeChain(isolate, inner_scope, position);
       return;
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8