Add an interface for Flash to clear its data.

ppapi/proxy/ppapi_messages.h

Index: ppapi/proxy/ppapi_messages.h
diff --git a/ppapi/proxy/ppapi_messages.h b/ppapi/proxy/ppapi_messages.h
index 0a2dcf26ed2de90e9c025b17743974a25ebd3164..4601d66d6728cbd5dea0132e461dbe0c7138be49 100644
--- a/ppapi/proxy/ppapi_messages.h
+++ b/ppapi/proxy/ppapi_messages.h
@@ -243,8 +243,17 @@ IPC_SYNC_MESSAGE_CONTROL1_1(PpapiMsg_SupportsInterface,
                             std::string /* interface_name */,
                             bool /* result */)
 
-// Broker Process.
+// Instructs the plugin to clear data for the given site & time. The plugin
+// process will respond with PpapiHostMsg_ClearSiteDataResult.
+IPC_MESSAGE_CONTROL4(PpapiMsg_ClearSiteData,
+                     FilePath /* profile_path */,
+                     std::string /* site */,
+                     uint64 /* flags */,
+                     uint64 /* max_age */)
+IPC_MESSAGE_CONTROL1(PpapiHostMsg_ClearSiteDataResult,
+                     bool /* success */)
 
+// Broker Process.
 IPC_SYNC_MESSAGE_CONTROL2_1(PpapiMsg_ConnectToPlugin,
                             PP_Instance /* instance */,
                             IPC::PlatformFileForTransit /* handle */,