PNaCl on-demand installs: Make a separate async IPC to check if PNaCl is installed

components/nacl/common/nacl_host_messages.h

Index: components/nacl/common/nacl_host_messages.h
diff --git a/components/nacl/common/nacl_host_messages.h b/components/nacl/common/nacl_host_messages.h
index 0f3df7e9a69b78bb3d4107a211f96677e38f5ccc..3bff881471bc4d5e9cb85335e86575ef6c3e5fca 100644
--- a/components/nacl/common/nacl_host_messages.h
+++ b/components/nacl/common/nacl_host_messages.h
@@ -53,6 +53,24 @@ IPC_SYNC_MESSAGE_CONTROL1_2(NaClHostMsg_LaunchNaCl,
                             std::string /* error_message */)
 
 // A renderer sends this to the browser process when it wants to
+// ensure that PNaCl is installed.
+IPC_MESSAGE_CONTROL1(NaClHostMsg_EnsurePnaclInstalled,
+                     int /* pp_instance */)
+
+// The browser replies to the renderer's request to ensure that
+// PNaCl is installed.
+IPC_MESSAGE_CONTROL2(NaClViewMsg_EnsurePnaclInstalledReply,
+                     int /* pp_instance */,
+                     bool /* success */)
+
+// The browser may send a progress event for the renderer's request
+// to ensure that PNaCl is installed.
+IPC_MESSAGE_CONTROL3(NaClViewMsg_EnsurePnaclInstalledProgress,
+                     int /* pp_instance */,
+                     int64 /* current_progress */,
+                     int64 /* total */)
+
+// A renderer sends this to the browser process when it wants to
 // open a file for from the Pnacl component directory.
 IPC_SYNC_MESSAGE_CONTROL1_1(NaClHostMsg_GetReadonlyPnaclFD,
                             std::string /* name of requested PNaCl file */,