Make o.o.p. proxy handle PPP_Instance versions 0.4 and 0.5.

ppapi/proxy/host_dispatcher.cc

Index: ppapi/proxy/host_dispatcher.cc
diff --git a/ppapi/proxy/host_dispatcher.cc b/ppapi/proxy/host_dispatcher.cc
index c00390bf3245716b227c0d7636d495d9cf7527d2..35143be71d5e9bd47f1b114eeec6ff56908a0f1a 100644
--- a/ppapi/proxy/host_dispatcher.cc
+++ b/ppapi/proxy/host_dispatcher.cc
@@ -75,9 +75,6 @@ HostDispatcher::HostDispatcher(base::ProcessHandle remote_process_handle,
           local_get_interface(PPB_VAR_DEPRECATED_INTERFACE));
   SetSerializationRules(new HostVarSerializationRules(var_interface, module));
 
-  memset(plugin_interface_support_, 0,
-         sizeof(PluginInterfaceSupport) * INTERFACE_ID_COUNT);
-
   ppb_proxy_ = reinterpret_cast<const PPB_Proxy_Private*>(
       GetLocalInterface(PPB_PROXY_PRIVATE_INTERFACE));
   DCHECK(ppb_proxy_) << "The proxy interface should always be supported.";
@@ -208,21 +205,19 @@ const void* HostDispatcher::GetProxiedInterface(const std::string& interface) {
   if (!info)
     return NULL;
 
-  if (plugin_interface_support_[static_cast<int>(info->id)] !=
-      INTERFACE_UNQUERIED) {
-    // Already queried the plugin if it supports this interface.
-    if (plugin_interface_support_[info->id] == INTERFACE_SUPPORTED)
-      return info->interface_ptr;
-    return NULL;
+  PluginIFSupportMap::iterator iter(plugin_if_support_.find(interface));
+  if (iter == plugin_if_support_.end()) {
+    // Need to query. Cache the result so we only do this once.
+    bool supported = false;
+    Send(new PpapiMsg_SupportsInterface(interface, &supported));
+    std::pair<PluginIFSupportMap::iterator, bool> iter_success_pair;
+    iter_success_pair = plugin_if_support_.insert(
+        PluginIFSupportMap::value_type(interface,
+                                       supported ? INTERFACE_SUPPORTED :
+                                                   INTERFACE_UNSUPPORTED));
+    iter = iter_success_pair.first;
   }
-
-  // Need to re-query. Cache the result so we only do this once.
-  bool supported = false;
-  Send(new PpapiMsg_SupportsInterface(interface, &supported));
-  plugin_interface_support_[static_cast<int>(info->id)] =
-      supported ? INTERFACE_SUPPORTED : INTERFACE_UNSUPPORTED;
-
-  if (supported)
+  if (iter->second == INTERFACE_SUPPORTED)
     return info->interface_ptr;
   return NULL;
 }