Add ramdisk image.

It is similar to recovery image.
Test: m nothing -j

Change-Id: I11389777c6bfb0c0d73bbb4c70091c1e70f44077
diff --git a/android/paths.go b/android/paths.go
index 02f56d0..7bfd8e1 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -49,6 +49,7 @@
 	InstallInData() bool
 	InstallInTestcases() bool
 	InstallInSanitizerDir() bool
+	InstallInRamdisk() bool
 	InstallInRecovery() bool
 	InstallInRoot() bool
 	InstallBypassMake() bool
@@ -1254,6 +1255,9 @@
 		partition = "data"
 	} else if ctx.InstallInTestcases() {
 		partition = "testcases"
+	} else if ctx.InstallInRamdisk() {
+		// TODO(elsk): should be conditional on RECOVERY_AS_BOOT
+		partition = "ramdisk"
 	} else if ctx.InstallInRecovery() {
 		if ctx.InstallInRoot() {
 			partition = "recovery/root"