Enable PDF accessibility when RenderFrame's accessibility mode changes.

content/public/renderer/pepper_plugin_instance.h

Index: content/public/renderer/pepper_plugin_instance.h
diff --git a/content/public/renderer/pepper_plugin_instance.h b/content/public/renderer/pepper_plugin_instance.h
index 470bf664bf140055d4c7a2d6ccae74d4d027af08..46de4fe6a960747621ff48576b7c013206bdca1b 100644
--- a/content/public/renderer/pepper_plugin_instance.h
+++ b/content/public/renderer/pepper_plugin_instance.h
@@ -46,6 +46,7 @@ class Isolate;
 }
 
 namespace content {
+class RenderFrame;
 class RenderView;
 
 class PepperPluginInstance {
@@ -56,6 +57,8 @@ class PepperPluginInstance {
 
   virtual ~PepperPluginInstance() {}
 
+  virtual content::RenderFrame* GetRenderFrame() = 0;
+
   virtual content::RenderView* GetRenderView() = 0;
 
   virtual blink::WebPluginContainer* GetContainer() = 0;