apex: Deprecate legacy_android10_support prop

min_sdk_version = 29 implies that the module should support Android10.

Bug: 150431944
Test: m
Change-Id: Iad90a239898f59456900ae7816b90379b1b43406
diff --git a/android/apex.go b/android/apex.go
index eb79123..eabe059 100644
--- a/android/apex.go
+++ b/android/apex.go
@@ -21,13 +21,14 @@
 	"sync"
 )
 
+const (
+	SdkVersion_Android10 = 29
+)
+
 type ApexInfo struct {
 	// Name of the apex variant that this module is mutated into
 	ApexName string
 
-	// Whether this apex variant needs to target Android 10
-	LegacyAndroid10Support bool
-
 	MinSdkVersion int
 }
 
@@ -207,7 +208,7 @@
 }
 
 func (m *ApexModuleBase) ShouldSupportAndroid10() bool {
-	return !m.IsForPlatform() && (m.ApexProperties.Info.MinSdkVersion <= 29 || m.ApexProperties.Info.LegacyAndroid10Support)
+	return !m.IsForPlatform() && (m.ApexProperties.Info.MinSdkVersion <= SdkVersion_Android10)
 }
 
 func (m *ApexModuleBase) checkApexAvailableProperty(mctx BaseModuleContext) {