Add cross-origin loading of NEXEs for MIME type handlers

src/trusted/plugin/ppapi/plugin_ppapi.cc

Index: src/trusted/plugin/ppapi/plugin_ppapi.cc
===================================================================
--- src/trusted/plugin/ppapi/plugin_ppapi.cc	(revision 4887)
+++ src/trusted/plugin/ppapi/plugin_ppapi.cc	(working copy)
@@ -38,6 +38,7 @@
 // The "src" attribute of the <embed> tag. The value is expected to be a URL
 // pointing to the nexe (aka nacl module) file.
 const char* const kSrcAttribute = "src";
+const char* const kTypeAttribute = "type";
 // The "nacl" attribute of the <embed> tag.  The value is expected to be either
 // a URL or URI pointing to the manifest file (which is expected to contain
 // JSON matching ISAs with .nexe URLs).
@@ -68,6 +69,8 @@
 
 }  // namespace
 
+const char* const kNaClMIMEType = "application/x-nacl";
+
 bool PluginPpapi::SetAsyncCallback(void* obj, SrpcParams* params) {
   PluginPpapi* plugin =
       static_cast<PluginPpapi*>(reinterpret_cast<Plugin*>(obj));
@@ -144,6 +147,12 @@
       const_cast<char**>(argn),
       const_cast<char**>(argv));
   if (status) {
+    const char* type_attr = LookupArgument(kTypeAttribute);
+    if (type_attr != NULL) {
+      mime_type_ = nacl::string(type_attr);
+      std::transform(mime_type_.begin(), mime_type_.end(), mime_type_.begin(),
+                     tolower);
+    }
     // Note: The order of attribute lookup is important.  This pattern looks
     // for a "nacl" attribute first, then a "src" attribute.
     const char* nacl_attr = LookupArgument(kNaclManifestAttribute);