Use precompiled headers for most large projects.

ppapi/proxy/ppapi_proxy_test.cc

Index: ppapi/proxy/ppapi_proxy_test.cc
diff --git a/ppapi/proxy/ppapi_proxy_test.cc b/ppapi/proxy/ppapi_proxy_test.cc
index 89ffa9f4c9e81d1c6bef851019b307b1f9b04faf..76034d7541536276cecadd55b32af8ba27904f98 100644
--- a/ppapi/proxy/ppapi_proxy_test.cc
+++ b/ppapi/proxy/ppapi_proxy_test.cc
@@ -105,8 +105,8 @@ const void* ProxyTestHarnessBase::GetInterface(const char* name) {
 }
 
 void ProxyTestHarnessBase::RegisterTestInterface(const char* name,
-                                                 const void* interface) {
-  registered_interfaces_[name] = interface;
+                                                 const void* test_interface) {
+  registered_interfaces_[name] = test_interface;
 }
 
 bool ProxyTestHarnessBase::SupportsInterface(const char* name) {