Remove the redundant declaration

PluginInstance was declared twice so removing redundant declaration

Review URL: https://chromiumcodereview.appspot.com/13976005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195250 0039d316-1c4b-4281-b951-d872f2087c98

AUTHORS

@@ -237,3 +237,4 @@ Kenneth Rohde Christiansen <kenneth.r.christiansen@intel.com>
 Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
 Yandex LLC <*@yandex-team.ru>
 Yoshinori Sano <yoshinori.sano@gmail.com>
+Mrunal Kapade <mrunal.kapade@intel.com>

content/public/renderer/renderer_ppapi_host.h

@@ -32,12 +32,6 @@ class PpapiHost;
 }
 }
 
-namespace webkit {
-namespace ppapi {
-class PluginInstance;
-}
-}
-
 namespace WebKit {
 class WebPluginContainer;
 }