[avb_footer] Add avb_gen_vbmeta_image to generate vbmeta image

This is the reland of the change aosp/2375848. The build of initrd on
linux-x86 that has incorrect format (b/264940248) is disabled in this
cl.

Bug: 260821553
Test: m microdroid_kernel_signed and inspect the output using `avbtool
    info_image --image <output>`
Change-Id: I3ad2419b7132cde4b2fc34ddfa09ec5ba2166819

filesystem/filesystem_test.go

@@ -126,8 +126,34 @@ func TestFileSystemGathersItemsOnlyInSystemPartition(t *testing.T) {
 	android.AssertDeepEquals(t, "entries should have foo only", []string{"components/foo"}, module.entries)
 }
 
+func TestAvbGenVbmetaImage(t *testing.T) {
+	result := fixture.RunTestWithBp(t, `
+		avb_gen_vbmeta_image {
+			name: "input_hashdesc",
+			src: "input.img",
+			partition_name: "input_partition_name",
+			salt: "2222",
+		}`)
+	cmd := result.ModuleForTests("input_hashdesc", "android_arm64_armv8-a").Rule("avbGenVbmetaImage").RuleParams.Command
+	android.AssertStringDoesContain(t, "Can't find correct --partition_name argument",
+		cmd, "--partition_name input_partition_name")
+	android.AssertStringDoesContain(t, "Can't find --do_not_append_vbmeta_image",
+		cmd, "--do_not_append_vbmeta_image")
+	android.AssertStringDoesContain(t, "Can't find --output_vbmeta_image",
+		cmd, "--output_vbmeta_image ")
+	android.AssertStringDoesContain(t, "Can't find --salt argument",
+		cmd, "--salt 2222")
+}
+
 func TestAvbAddHashFooter(t *testing.T) {
 	result := fixture.RunTestWithBp(t, `
+		avb_gen_vbmeta_image {
+			name: "input_hashdesc",
+			src: "input.img",
+			partition_name: "input",
+			salt: "2222",
+		}
+
 		avb_add_hash_footer {
 			name: "myfooter",
 			src: "input.img",
@@ -145,6 +171,7 @@ func TestAvbAddHashFooter(t *testing.T) {
 					file: "value_file",
 				},
 			],
+			include_descriptors_from_images: ["input_hashdesc"],
 		}
 	`)
 	cmd := result.ModuleForTests("myfooter", "android_arm64_armv8-a").Rule("avbAddHashFooter").RuleParams.Command
@@ -158,4 +185,6 @@ func TestAvbAddHashFooter(t *testing.T) {
 		cmd, "--prop 'prop1:value1'")
 	android.AssertStringDoesContain(t, "Can't find --prop_from_file argument",
 		cmd, "--prop_from_file 'prop2:value_file'")
+	android.AssertStringDoesContain(t, "Can't find --include_descriptors_from_image",
+		cmd, "--include_descriptors_from_image ")
 }