Plugin Placeholders: Factor out common BindWebFrame method into base class.

components/plugins/renderer/plugin_placeholder.cc

Index: components/plugins/renderer/plugin_placeholder.cc
diff --git a/components/plugins/renderer/plugin_placeholder.cc b/components/plugins/renderer/plugin_placeholder.cc
index 8bbe491c405cded2a3c55e8613179f48ee962fb1..328e381ada063df65cee7800c61f535342f1658a 100644
--- a/components/plugins/renderer/plugin_placeholder.cc
+++ b/components/plugins/renderer/plugin_placeholder.cc
@@ -5,6 +5,8 @@
 #include "components/plugins/renderer/plugin_placeholder.h"
 
 #include "content/public/renderer/render_frame.h"
+#include "gin/handle.h"
+#include "third_party/WebKit/public/web/WebKit.h"
 
 namespace plugins {
 
@@ -32,6 +34,18 @@ const blink::WebPluginParams& PluginPlaceholder::GetPluginParams() const {
   return plugin_params_;
 }
 
+void PluginPlaceholder::BindWebFrame(blink::WebFrame* frame) {
+  v8::Isolate* isolate = blink::mainThreadIsolate();
+  v8::HandleScope handle_scope(isolate);
+  v8::Local<v8::Context> context = frame->mainWorldScriptContext();
+  DCHECK(!context.IsEmpty());
+
+  v8::Context::Scope context_scope(context);
+  v8::Local<v8::Object> global = context->Global();
+  global->Set(gin::StringToV8(isolate, "plugin"),
+              gin::CreateHandle(isolate, this).ToV8());
+}
+
 void PluginPlaceholder::ShowContextMenu(const blink::WebMouseEvent& event) {
   // Does nothing by default. Will be overridden if a specific browser wants
   // a context menu.