Log whether an event happened during landscape mode or not
b/38211234

<sample log>
  action:TAP
  Source child:APP_ICON, packageHash=-1046965711, componentHash=-371608779, intentHash=208792422, grid(4,4), span(1,1), pageIdx=0	parent:WORKSPACE id=0
  Elapsed container 3071 ms session 3071 ms action 0 ms
  isInLandscapeMode true
  isInMultiWindowMode false
</sample log>

Change-Id: I44dfe4e7ee2a41c56a50cc2b507bbbeedc458018
diff --git a/protos/launcher_log.proto b/protos/launcher_log.proto
index 909a429..93e09ae 100644
--- a/protos/launcher_log.proto
+++ b/protos/launcher_log.proto
@@ -156,4 +156,5 @@
   optional int64 elapsed_session_millis = 6;
 
   optional bool is_in_multi_window_mode = 7;
+  optional bool is_in_landscape_mode = 8;
 }