Add "legacy_android10_support" to "apex"

APEXes with "legacy_android10_support" will have apex_manifest.json for
compatibility as well as apex_manifest.pb.

Bug: 143951586
Test: m (soong tests)
Change-Id: I019252aee5a9423f4b180ba1026e6e99c9961437
diff --git a/apex/apex.go b/apex/apex.go
index 81c1230..0fa3b2a 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -343,6 +343,10 @@
 	// Whenever apex_payload.img of the APEX should include dm-verity hashtree.
 	// Should be only used in tests#.
 	Test_only_no_hashtree *bool
+
+	// Whether this APEX should support Android10. Default is false. If this is set true, then apex_manifest.json is bundled as well
+	// because Android10 requires legacy apex_manifest.json instead of apex_manifest.pb
+	Legacy_android10_support *bool
 }
 
 type apexTargetBundleProperties struct {
@@ -507,10 +511,8 @@
 	artApex         bool
 	primaryApexType bool
 
-	// intermediate path for apex_manifest.json
-	manifestJsonOut     android.WritablePath
-	manifestJsonFullOut android.WritablePath
-	manifestPbOut       android.WritablePath
+	manifestJsonOut android.WritablePath
+	manifestPbOut   android.WritablePath
 
 	// list of commands to create symlinks for backward compatibility
 	// these commands will be attached as LOCAL_POST_INSTALL_CMD to