Blink GC plugin: disallow own pointers to GC allocated collections.

tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp

 // Copyright 2014 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.
 
 // This clang plugin checks various invariants of the Blink garbage
 // collection infrastructure.
 //
 // Errors are described at:
 // http://www.chromium.org/developers/blink-gc-plugin-errors
 
@@ skipping 468 matching lines @@
     for (RecordInfo::Fields::iterator it = info->GetFields().begin();
          it != info->GetFields().end();
          ++it) {
       context().clear();
       current_ = &it->second;
       current_->edge()->Accept(this);
     }
     return !invalid_fields_.empty();
   }
 
-  void VisitMember(Member* edge) override {
+  void AtMember(Member* edge) override {
     if (managed_host_)
       return;
     // A member is allowed to appear in the context of a root.
     for (Context::iterator it = context().begin();
          it != context().end();
          ++it) {
       if ((*it)->Kind() == Edge::kRoot)
         return;
     }
     invalid_fields_.push_back(std::make_pair(current_, kMemberInUnmanaged));
   }
 
-  void VisitValue(Value* edge) override {
+  void AtValue(Value* edge) override {
     // TODO: what should we do to check unions?
     if (edge->value()->record()->isUnion())
       return;
 
     if (!stack_allocated_host_ && edge->value()->IsStackAllocated()) {
       invalid_fields_.push_back(std::make_pair(current_, kPtrFromHeapToStack));
       return;
     }
 
     if (!Parent() &&
@@ skipping 20 matching lines @@
       return;
     }
 
     if (Parent()->IsRawPtr() || Parent()->IsRefPtr() || Parent()->IsOwnPtr()) {
       invalid_fields_.push_back(std::make_pair(
           current_, InvalidSmartPtr(Parent())));
       return;
     }
   }
 
+  void AtCollection(Collection* edge) override {
+    if (edge->on_heap() && Parent() && Parent()->IsOwnPtr())
+      invalid_fields_.push_back(std::make_pair(current_, kOwnPtrToGCManaged));
+  }
+
  private:
   Error InvalidSmartPtr(Edge* ptr) {
     if (ptr->IsRawPtr())
       return kRawPtrToGCManaged;
     if (ptr->IsRefPtr())
       return kRefPtrToGCManaged;
     if (ptr->IsOwnPtr())
       return kOwnPtrToGCManaged;
     assert(false && "Unknown smart pointer kind");
   }
@@ skipping 919 matching lines @@
 
  private:
   BlinkGCPluginOptions options_;
 };
 
 }  // namespace
 
 static FrontendPluginRegistry::Add<BlinkGCPluginAction> X(
     "blink-gc-plugin",
     "Check Blink GC invariants");