Update Blink GC plugin to reflect that Oilpan is now always enabled.

tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp

Index: tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp
diff --git a/tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp b/tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp
index 558637c9c190b5489e0ddccf37b0c62f921568af..b4eb04b5d0d88aecd8d7ed8bdb8ac233b30d0108 100644
--- a/tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp
+++ b/tools/clang/blink_gc_plugin/CheckFieldsVisitor.cpp
@@ -85,38 +85,22 @@ void CheckFieldsVisitor::AtValue(Value* edge) {
   if (!Parent() || !edge->value()->IsGCAllocated())
     return;
 
-  // In transition mode, disallow  OwnPtr<T>, RawPtr<T> to GC allocated T's,
-  // also disallow T* in stack-allocated types.
-  if (options_.enable_oilpan) {
-    if (Parent()->IsOwnPtr() ||
-        Parent()->IsRawPtrClass() ||
-        (stack_allocated_host_ && Parent()->IsRawPtr())) {
-      invalid_fields_.push_back(std::make_pair(
-          current_, InvalidSmartPtr(Parent())));
-      return;
-    }
-    if (options_.warn_raw_ptr && Parent()->IsRawPtr()) {
-      if (static_cast<RawPtr*>(Parent())->HasReferenceType()) {
-        invalid_fields_.push_back(std::make_pair(
-            current_, kReferencePtrToGCManagedWarning));
-      } else {
-        invalid_fields_.push_back(std::make_pair(
-            current_, kRawPtrToGCManagedWarning));
-      }
-    }
-    return;
-  }
-
-  if (Parent()->IsRawPtr() || Parent()->IsOwnPtr()) {
+  // Disallow  OwnPtr<T>, RefPtr<T> and T* to stack-allocated types.
+  if (Parent()->IsOwnPtr() ||
+      (Parent()->IsRefPtr() && !edge->value()->IsGCRefCounted()) ||

[sof, 2016/04/18 21:23:15]

Note: this RefPtr<T> check wasn't previously done with enable-oilpan, but now
is. (There is test coverage for this, but it implicitly relied on the test being
run without enable-oilpan..)

I think it has merit to catch&report such misuse of RefPtr<> as a plugin error,
but code using it will fail for other reasons as well. (e.g., no ref()/deref()
present on T.)

+      (stack_allocated_host_ && Parent()->IsRawPtr())) {
     invalid_fields_.push_back(std::make_pair(
         current_, InvalidSmartPtr(Parent())));
     return;
   }
-
-  if (Parent()->IsRefPtr() && !edge->value()->IsGCRefCounted()) {
-    invalid_fields_.push_back(std::make_pair(
-        current_, InvalidSmartPtr(Parent())));
-    return;
+  if (options_.warn_raw_ptr && Parent()->IsRawPtr()) {
+    if (static_cast<RawPtr*>(Parent())->HasReferenceType()) {
+      invalid_fields_.push_back(std::make_pair(
+          current_, kReferencePtrToGCManagedWarning));
+    } else {
+      invalid_fields_.push_back(std::make_pair(
+          current_, kRawPtrToGCManagedWarning));
+    }
   }
 }