Rename InputWindowHandle hasFocus to focusable

A window with hasFocus set to true, means the window can be focusable.
The current name is confusing when mutliple windows set the field to
true. Rename this to focusable and also remove canRecieveKeys field which
is not used.

Test: presubmit
Bug: 151179149
Change-Id: I38f63dfd08300b6fc97388ee6d8bcbdddb89c4a1
diff --git a/services/surfaceflinger/layerproto/layers.proto b/services/surfaceflinger/layerproto/layers.proto
index 41d6d08..f3f5626 100644
--- a/services/surfaceflinger/layerproto/layers.proto
+++ b/services/surfaceflinger/layerproto/layers.proto
@@ -193,8 +193,8 @@
 
     uint32 surface_inset = 5;
     bool visible = 6;
-    bool can_receive_keys = 7;
-    bool has_focus = 8;
+    bool can_receive_keys = 7  [deprecated=true];
+    bool focusable = 8;
     bool has_wallpaper = 9;
 
     float global_scale_factor = 10;