GN: Use std::unique_ptr for owning pointers in Scope::NamedScopeMap.

tools/gn/scope.cc

 // Copyright (c) 2013 The Chromium 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 "tools/gn/scope.h"
 
 #include "base/logging.h"
-#include "base/stl_util.h"
+#include "base/memory/ptr_util.h"
 #include "tools/gn/parse_tree.h"
 #include "tools/gn/template.h"
 
 namespace {
 
 // FLags set in the mode_flags_ of a scope. If a bit is set, it applies
 // recursively to all dependent scopes.
 const unsigned kProcessingBuildConfigFlag = 1;
 const unsigned kProcessingImportFlag = 2;
 
@@ skipping 38 matching lines @@
 
 Scope::Scope(const Scope* parent)
     : const_containing_(parent),
       mutable_containing_(nullptr),
       settings_(parent->settings()),
       mode_flags_(0),
       item_collector_(nullptr) {
 }
 
 Scope::~Scope() {
-  STLDeleteContainerPairSecondPointers(target_defaults_.begin(),
-                                       target_defaults_.end());
 }
 
 const Value* Scope::GetValue(const base::StringPiece& ident,
                              bool counts_as_used) {
   // First check for programmatically-provided values.
   for (const auto& provider : programmatic_providers_) {
     const Value* v = provider->GetProgrammaticValue(ident);
     if (v)
       return v;
   }
@@ skipping 229 matching lines @@
         *err = Err(node_for_err, "Target defaults collision.",
             "This " + desc_string + " contains target defaults for\n"
             "\"" + current_name + "\" which would clobber one for the\n"
             "same target type in your current scope. It's unfortunate that I'm "
             "too stupid\nto tell you the location of where the target defaults "
             "were set. Usually\nthis happens in the BUILDCONFIG.gn file.");
         return false;
       }
     }
 
-    // Be careful to delete any pointer we're about to clobber.
-    Scope** dest_scope = &dest->target_defaults_[current_name];
-    if (*dest_scope)
-      delete *dest_scope;
-    *dest_scope = new Scope(settings_);
-    pair.second->NonRecursiveMergeTo(*dest_scope, options, node_for_err,
+    std::unique_ptr<Scope>& dest_scope = dest->target_defaults_[current_name];
+    dest_scope = base::WrapUnique(new Scope(settings_));
+    pair.second->NonRecursiveMergeTo(dest_scope.get(), options, node_for_err,
                                      "<SHOULDN'T HAPPEN>", err);
   }
 
   // Sources assignment filter.
   if (sources_assignment_filter_) {
     if (!options.clobber_existing) {
       if (dest->GetSourcesAssignmentFilter()) {
         // Sources assignment filter present in both the source and the dest.
         std::string desc_string(desc_for_err);
         *err = Err(node_for_err, "Assignment filter collision.",
@@ skipping 71 matching lines @@
   NonRecursiveMergeTo(result.get(), options, nullptr, "<SHOULDN'T HAPPEN>",
                       &err);
   DCHECK(!err.has_error());
   return result;
 }
 
 Scope* Scope::MakeTargetDefaults(const std::string& target_type) {
   if (GetTargetDefaults(target_type))
     return nullptr;
 
-  Scope** dest = &target_defaults_[target_type];
-  if (*dest) {
+  std::unique_ptr<Scope>& dest = target_defaults_[target_type];
+  if (dest) {
     NOTREACHED();  // Already set.
-    return *dest;
+    return dest.get();
   }
-  *dest = new Scope(settings_);
-  return *dest;
+  dest = base::WrapUnique(new Scope(settings_));
+  return dest.get();
 }
 
 const Scope* Scope::GetTargetDefaults(const std::string& target_type) const {
   NamedScopeMap::const_iterator found = target_defaults_.find(target_type);
   if (found != target_defaults_.end())
-    return found->second;
+    return found->second.get();
   if (containing())
     return containing()->GetTargetDefaults(target_type);
   return nullptr;
 }
 
 const PatternList* Scope::GetSourcesAssignmentFilter() const {
   if (sources_assignment_filter_)
     return sources_assignment_filter_.get();
   if (containing())
     return containing()->GetSourcesAssignmentFilter();
@@ skipping 74 matching lines @@
 }
 
 void Scope::AddProvider(ProgrammaticProvider* p) {
   programmatic_providers_.insert(p);
 }
 
 void Scope::RemoveProvider(ProgrammaticProvider* p) {
   DCHECK(programmatic_providers_.find(p) != programmatic_providers_.end());
   programmatic_providers_.erase(p);
 }