Pepper: Move GetSandboxISA() to PPB_NaCl_Private.

ppapi/native_client/src/trusted/plugin/pnacl_resources.cc

Index: ppapi/native_client/src/trusted/plugin/pnacl_resources.cc
diff --git a/ppapi/native_client/src/trusted/plugin/pnacl_resources.cc b/ppapi/native_client/src/trusted/plugin/pnacl_resources.cc
index 6ed851302487d2f959c15d1e982d2624793ec78f..e75e19d6867e9a1317e4c239041ae3296b24ea70 100644
--- a/ppapi/native_client/src/trusted/plugin/pnacl_resources.cc
+++ b/ppapi/native_client/src/trusted/plugin/pnacl_resources.cc
@@ -17,6 +17,14 @@
 #include "third_party/jsoncpp/source/include/json/value.h"
 
 namespace plugin {
+namespace {
+const PPB_NaCl_Private* GetNaClInterface() {
+  pp::Module *module = pp::Module::Get();
+  CHECK(module);
+  return static_cast<const PPB_NaCl_Private*>(
+      module->GetBrowserInterface(PPB_NACL_PRIVATE_INTERFACE));
+}
+}  // namespace
 
 static const char kPnaclBaseUrl[] = "chrome://pnacl-translator/";
 const char PnaclUrls::kResourceInfoUrl[] = "pnacl.json";
@@ -26,7 +34,7 @@ nacl::string PnaclUrls::GetBaseUrl() {
 }
 
 nacl::string PnaclUrls::PrependPlatformPrefix(const nacl::string& url) {
-  return nacl::string(GetSandboxISA()) + "/" + url;
+  return nacl::string(GetNaClInterface()->GetSandboxISA()) + "/" + url;
 }
 
 // Determine if a URL is for a pnacl-component file, or if it is some other