Add TestingInstance::EvalScript method which posts a message that the test page can eval().

ppapi/proxy/ppb_testing_proxy.h

Index: ppapi/proxy/ppb_testing_proxy.h
===================================================================
--- ppapi/proxy/ppb_testing_proxy.h	(revision 114053)
+++ ppapi/proxy/ppb_testing_proxy.h	(working copy)
@@ -8,6 +8,7 @@
 #include "base/basictypes.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
+#include "ppapi/c/pp_var.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/shared_impl/host_resource.h"
 
@@ -20,6 +21,10 @@
 
 namespace proxy {
 
+class SerializedVarReceiveInput;
+class SerializedVarOutParam;
+class SerializedVarReturnValue;
+
 class PPB_Testing_Proxy : public InterfaceProxy {
  public:
   PPB_Testing_Proxy(Dispatcher* dispatcher);
@@ -41,6 +46,10 @@
   void OnMsgGetLiveObjectsForInstance(PP_Instance instance, uint32_t* result);
   void OnMsgSimulateInputEvent(PP_Instance instance,
                                const ppapi::InputEventData& input_event);
+  void OnMsgExecuteScript(PP_Instance instance,
+                          SerializedVarReceiveInput script,
+                          SerializedVarOutParam out_exception,
+                          SerializedVarReturnValue result);
 
   // When this proxy is in the host side, this value caches the interface
   // pointer so we don't have to retrieve it from the dispatcher each time.