Remove _API_FILE variables

There are no known usages of these variables, and many have been
incorrectly set for a long time.

Also convert the <module> phony for api txt to androidmk.

Bug: 152479829
Test: m
Change-Id: Iff355041d88eb59ac47dd19a03e993cf1ce3927e
diff --git a/java/androidmk.go b/java/androidmk.go
index d37eac8..bbf2c33 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -472,34 +472,6 @@
 				if ddoc.Javadoc.stubsSrcJar != nil {
 					entries.SetPath("LOCAL_DROIDDOC_STUBS_SRCJAR", ddoc.Javadoc.stubsSrcJar)
 				}
-				apiFilePrefix := "INTERNAL_PLATFORM_"
-				if String(ddoc.properties.Api_tag_name) != "" {
-					apiFilePrefix += String(ddoc.properties.Api_tag_name) + "_"
-				}
-				if ddoc.apiFile != nil {
-					entries.SetPath(apiFilePrefix+"API_FILE", ddoc.apiFile)
-				}
-				if ddoc.dexApiFile != nil {
-					entries.SetPath(apiFilePrefix+"DEX_API_FILE", ddoc.dexApiFile)
-				}
-				if ddoc.privateApiFile != nil {
-					entries.SetPath(apiFilePrefix+"PRIVATE_API_FILE", ddoc.privateApiFile)
-				}
-				if ddoc.privateDexApiFile != nil {
-					entries.SetPath(apiFilePrefix+"PRIVATE_DEX_API_FILE", ddoc.privateDexApiFile)
-				}
-				if ddoc.removedApiFile != nil {
-					entries.SetPath(apiFilePrefix+"REMOVED_API_FILE", ddoc.removedApiFile)
-				}
-				if ddoc.removedDexApiFile != nil {
-					entries.SetPath(apiFilePrefix+"REMOVED_DEX_API_FILE", ddoc.removedDexApiFile)
-				}
-				if ddoc.exactApiFile != nil {
-					entries.SetPath(apiFilePrefix+"EXACT_API_FILE", ddoc.exactApiFile)
-				}
-				if ddoc.proguardFile != nil {
-					entries.SetPath(apiFilePrefix+"PROGUARD_FILE", ddoc.proguardFile)
-				}
 			},
 		},
 		ExtraFooters: []android.AndroidMkExtraFootersFunc{
@@ -578,35 +550,18 @@
 				if dstubs.metadataZip != nil {
 					entries.SetPath("LOCAL_DROIDDOC_METADATA_ZIP", dstubs.metadataZip)
 				}
-				apiFilePrefix := "INTERNAL_PLATFORM_"
-				if String(dstubs.properties.Api_tag_name) != "" {
-					apiFilePrefix += String(dstubs.properties.Api_tag_name) + "_"
-				}
-				if dstubs.apiFile != nil {
-					entries.SetPath(apiFilePrefix+"API_FILE", dstubs.apiFile)
-				}
-				if dstubs.dexApiFile != nil {
-					entries.SetPath(apiFilePrefix+"DEX_API_FILE", dstubs.dexApiFile)
-				}
-				if dstubs.privateApiFile != nil {
-					entries.SetPath(apiFilePrefix+"PRIVATE_API_FILE", dstubs.privateApiFile)
-				}
-				if dstubs.privateDexApiFile != nil {
-					entries.SetPath(apiFilePrefix+"PRIVATE_DEX_API_FILE", dstubs.privateDexApiFile)
-				}
-				if dstubs.removedApiFile != nil {
-					entries.SetPath(apiFilePrefix+"REMOVED_API_FILE", dstubs.removedApiFile)
-				}
-				if dstubs.removedDexApiFile != nil {
-					entries.SetPath(apiFilePrefix+"REMOVED_DEX_API_FILE", dstubs.removedDexApiFile)
-				}
-				if dstubs.exactApiFile != nil {
-					entries.SetPath(apiFilePrefix+"EXACT_API_FILE", dstubs.exactApiFile)
-				}
 			},
 		},
 		ExtraFooters: []android.AndroidMkExtraFootersFunc{
 			func(w io.Writer, name, prefix, moduleDir string, entries *android.AndroidMkEntries) {
+				if dstubs.apiFile != nil {
+					fmt.Fprintf(w, ".PHONY: %s %s.txt\n", dstubs.Name(), dstubs.Name())
+					fmt.Fprintf(w, "%s %s.txt: %s\n", dstubs.Name(), dstubs.Name(), dstubs.apiFile)
+				}
+				if dstubs.removedApiFile != nil {
+					fmt.Fprintf(w, ".PHONY: %s %s.txt\n", dstubs.Name(), dstubs.Name())
+					fmt.Fprintf(w, "%s %s.txt: %s\n", dstubs.Name(), dstubs.Name(), dstubs.removedApiFile)
+				}
 				if dstubs.checkCurrentApiTimestamp != nil {
 					fmt.Fprintln(w, ".PHONY:", dstubs.Name()+"-check-current-api")
 					fmt.Fprintln(w, dstubs.Name()+"-check-current-api:",