Put the Pepper stuff in the content namespace.

content/renderer/pepper/pepper_plugin_delegate_impl.h

Index: content/renderer/pepper/pepper_plugin_delegate_impl.h
diff --git a/content/renderer/pepper/pepper_plugin_delegate_impl.h b/content/renderer/pepper/pepper_plugin_delegate_impl.h
index 2988955c342f2f7600fa70b8a7ef676f306b4653..23ee7e74602eabe408614c52ee47ede271098ca4 100644
--- a/content/renderer/pepper/pepper_plugin_delegate_impl.h
+++ b/content/renderer/pepper/pepper_plugin_delegate_impl.h
@@ -29,10 +29,8 @@
 #include "webkit/plugins/ppapi/ppb_flash_menu_impl.h"
 
 class FilePath;
-class PepperBrokerImpl;
-class PepperDeviceEnumerationEventHandler;
-class PepperPluginDelegateImpl;
 class RenderViewImpl;
+class TransportDIB;
 
 namespace content {
 class GamepadSharedMemoryReader;
@@ -69,7 +67,12 @@ struct WebCompositionUnderline;
 struct WebFileChooserParams;
 }
 
-class TransportDIB;
+
+namespace content {
+
+class PepperBrokerImpl;
+class PepperDeviceEnumerationEventHandler;
+class PepperPluginDelegateImpl;
 
 class PepperPluginDelegateImpl
     : public webkit::ppapi::PluginDelegate,
@@ -484,4 +487,6 @@ class PepperPluginDelegateImpl
   DISALLOW_COPY_AND_ASSIGN(PepperPluginDelegateImpl);
 };
 
+}  // namespace content
+
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_PLUGIN_DELEGATE_IMPL_H_