Convert the pp::proxy namespace to the ppapi::proxy namespace.

ppapi/proxy/mock_resource.cc

Index: ppapi/proxy/mock_resource.cc
diff --git a/ppapi/proxy/mock_resource.cc b/ppapi/proxy/mock_resource.cc
index 2173eeaa5eee8d3ac71ea1d5f6475bcf896db05d..e79ab9a5e1071ac036fe560b8fa77f2d25b4ee86 100644
--- a/ppapi/proxy/mock_resource.cc
+++ b/ppapi/proxy/mock_resource.cc
@@ -4,10 +4,7 @@
 
 #include "ppapi/proxy/mock_resource.h"
 
-using ppapi::HostResource;
-using ppapi::Resource;
-
-namespace pp {
+namespace ppapi {
 namespace proxy {
 
 MockResource::MockResource(const HostResource& resource) : Resource(resource) {
@@ -17,4 +14,4 @@ MockResource::~MockResource() {
 }
 
 }  // namespace proxy
-}  // namespace pp
+}  // namespace ppapi