Use PluginPrefs in ChromePluginServiceFilter to check whether a plugin is enabled.

chrome/browser/browser_process_impl.cc

Index: chrome/browser/browser_process_impl.cc
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index d3ae1091c8d4fba486b818b43d6a47b117d1b830..669627ce920df2bc4542a120a3a02f89445ccbd8 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -20,6 +20,7 @@
 #include "chrome/browser/browser_main.h"
 #include "chrome/browser/browser_process_sub_thread.h"
 #include "chrome/browser/browser_trial.h"
+#include "chrome/browser/chrome_plugin_service_filter.h"
 #include "chrome/browser/component_updater/component_updater_configurator.h"
 #include "chrome/browser/component_updater/component_updater_service.h"
 #include "chrome/browser/debugger/devtools_protocol_handler.h"
@@ -734,7 +735,8 @@ void BrowserProcessImpl::CreateIOThread() {
   // it is predominantly used from the io thread, but must be created
   // on the main thread. The service ctor is inexpensive and does not
   // invoke the io_thread() accessor.
-  PluginService::GetInstance();
+  PluginService::GetInstance()->set_filter(
+      ChromePluginServiceFilter::GetInstance());
 
   // Add the Chrome specific plugins.
   chrome::RegisterInternalDefaultPlugin();