Reland: Plugin Placeholders: Refactor for platforms that don't support plugins

gin/wrappable.cc

Index: gin/wrappable.cc
diff --git a/gin/wrappable.cc b/gin/wrappable.cc
index 27c58dfdb01fe9c804f0e9157b67e15d5c911552..53a2f2549f1a809732adda9b9e87159b77d9116d 100644
--- a/gin/wrappable.cc
+++ b/gin/wrappable.cc
@@ -4,7 +4,6 @@
 
 #include "gin/wrappable.h"
 
-#include "base/logging.h"
 #include "gin/object_template_builder.h"
 #include "gin/per_isolate_data.h"
 
@@ -36,7 +35,7 @@ void WrappableBase::SecondWeakCallback(
 }
 
 v8::Local<v8::Object> WrappableBase::GetWrapperImpl(v8::Isolate* isolate,
-                                                     WrapperInfo* info) {
+                                                    WrapperInfo* info) {
   if (!wrapper_.IsEmpty()) {
     return v8::Local<v8::Object>::New(isolate, wrapper_);
   }
@@ -59,35 +58,12 @@ v8::Local<v8::Object> WrappableBase::GetWrapperImpl(v8::Isolate* isolate,
     return wrapper;
   }
   wrapper->SetAlignedPointerInInternalField(kWrapperInfoIndex, info);
+  // This needs to be adjusted with downcasting on retrieval, as this points
+  // to the WrapperBase object, which may not be the start of the whole object.
   wrapper->SetAlignedPointerInInternalField(kEncodedValueIndex, this);
   wrapper_.Reset(isolate, wrapper);
   wrapper_.SetWeak(this, FirstWeakCallback, v8::WeakCallbackType::kParameter);
   return wrapper;
 }
 
-namespace internal {
-
-void* FromV8Impl(v8::Isolate* isolate, v8::Local<v8::Value> val,
-                 WrapperInfo* wrapper_info) {
-  if (!val->IsObject())
-    return NULL;
-  v8::Local<v8::Object> obj = v8::Local<v8::Object>::Cast(val);
-  WrapperInfo* info = WrapperInfo::From(obj);
-
-  // If this fails, the object is not managed by Gin. It is either a normal JS
-  // object that's not wrapping any external C++ object, or it is wrapping some
-  // C++ object, but that object isn't managed by Gin (maybe Blink).
-  if (!info)
-    return NULL;
-
-  // If this fails, the object is managed by Gin, but it's not wrapping an
-  // instance of the C++ class associated with wrapper_info.
-  if (info != wrapper_info)
-    return NULL;
-
-  return obj->GetAlignedPointerFromInternalField(kEncodedValueIndex);
-}
-
-}  // namespace internal
-
 }  // namespace gin