Adding support for derivative apps to safely extend LauncherLog proto

Bug: 37676962
Change-Id: I24716070841b41418ac57b8dc367278e3ebdd046
diff --git a/protos/launcher_log.proto b/protos/launcher_log.proto
index 93e09ae..0bbec18 100644
--- a/protos/launcher_log.proto
+++ b/protos/launcher_log.proto
@@ -15,6 +15,8 @@
  */
 syntax = "proto2";
 
+import "launcher_log_extension.proto";
+
 option java_package = "com.android.launcher3.userevent";
 option java_outer_classname = "LauncherLogProto";
 
@@ -52,6 +54,7 @@
   optional int32 span_x = 13 [default = 1];// Used for ItemType.WIDGET
   optional int32 span_y = 14 [default = 1];// Used for ItemType.WIDGET
   optional int32 predictedRank = 15;
+  optional TargetExtension extension = 16;
 }
 
 // Used to define what type of item a Target would represent.
@@ -144,7 +147,6 @@
 //         Action (Touch) + Target + Target
 //
 message LauncherEvent {
-
   required Action action = 1;
 
   // List of targets that touch actions can be operated on.
@@ -157,4 +159,6 @@
 
   optional bool is_in_multi_window_mode = 7;
   optional bool is_in_landscape_mode = 8;
+
+  optional LauncherEventExtension extension = 9;
 }