Remove error from AndroidMkDataProvider.AndroidMk

It's never anything except nil, and it unnecessarily complicates
the implementations.

Test: m -j checkbuild
Change-Id: I3e3b7251f32ffa84dbdfd0448faf248c306ca808

android/androidmk.go

@@ -33,7 +33,7 @@ func init() {
 }
 
 type AndroidMkDataProvider interface {
-	AndroidMk() (AndroidMkData, error)
+	AndroidMk() AndroidMkData
 	BaseModuleName() string
 }
 

cc/androidmk.go

@@ -49,14 +49,17 @@ func (c *Module) subAndroidMk(data *android.AndroidMkData, obj interface{}) {
 	}
 }
 
-func (c *Module) AndroidMk() (ret android.AndroidMkData, err error) {
+func (c *Module) AndroidMk() android.AndroidMkData {
 	if c.Properties.HideFromMake {
-		ret.Disabled = true
-		return ret, nil
+		return android.AndroidMkData{
+			Disabled: true,
+		}
 	}
 
-	ret.OutputFile = c.outputFile
-	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
+	ret := android.AndroidMkData{
+		OutputFile: c.outputFile,
+		Extra: []android.AndroidMkExtraFunc{
+			func(w io.Writer, outputFile android.Path) {
 				fmt.Fprintln(w, "LOCAL_SANITIZE := never")
 				if len(c.Properties.AndroidMkSharedLibs) > 0 {
 					fmt.Fprintln(w, "LOCAL_SHARED_LIBRARIES := "+strings.Join(c.Properties.AndroidMkSharedLibs, " "))
@@ -71,7 +74,9 @@ func (c *Module) AndroidMk() (ret android.AndroidMkData, err error) {
 				if c.vndk() {
 					fmt.Fprintln(w, "LOCAL_USE_VNDK := true")
 				}
-	})
+			},
+		},
+	}
 
 	for _, feature := range c.features {
 		c.subAndroidMk(&ret, feature)
@@ -90,7 +95,7 @@ func (c *Module) AndroidMk() (ret android.AndroidMkData, err error) {
 		ret.SubName += vendorSuffix
 	}
 
-	return ret, nil
+	return ret
 }
 
 func androidMkWriteTestData(data android.Paths, ctx AndroidMkContext, ret *android.AndroidMkData) {

java/androidmk.go

@@ -21,20 +21,26 @@ import (
 	"android/soong/android"
 )
 
-func (library *Library) AndroidMk() (ret android.AndroidMkData, err error) {
-	ret.Class = "JAVA_LIBRARIES"
-	ret.OutputFile = android.OptionalPathForPath(library.outputFile)
-	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
+func (library *Library) AndroidMk() android.AndroidMkData {
+	return android.AndroidMkData{
+		Class:      "JAVA_LIBRARIES",
+		OutputFile: android.OptionalPathForPath(library.outputFile),
+		Extra: []android.AndroidMkExtraFunc{
+			func(w io.Writer, outputFile android.Path) {
 				fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := .jar")
-	})
-	return
+			},
+		},
+	}
 }
 
-func (prebuilt *Import) AndroidMk() (ret android.AndroidMkData, err error) {
-	ret.Class = "JAVA_LIBRARIES"
-	ret.OutputFile = android.OptionalPathForPath(prebuilt.combinedClasspathFile)
-	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
+func (prebuilt *Import) AndroidMk() android.AndroidMkData {
+	return android.AndroidMkData{
+		Class:      "JAVA_LIBRARIES",
+		OutputFile: android.OptionalPathForPath(prebuilt.combinedClasspathFile),
+		Extra: []android.AndroidMkExtraFunc{
+			func(w io.Writer, outputFile android.Path) {
 				fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := .jar")
-	})
-	return
+			},
+		},
+	}
 }

phony/phony.go

@@ -48,13 +48,14 @@ func (p *phony) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	}
 }
 
-func (p *phony) AndroidMk() (ret android.AndroidMkData, err error) {
-	ret.Custom = func(w io.Writer, name, prefix, moduleDir string) {
+func (p *phony) AndroidMk() android.AndroidMkData {
+	return android.AndroidMkData{
+		Custom: func(w io.Writer, name, prefix, moduleDir string) {
 			fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
 			fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
 			fmt.Fprintln(w, "LOCAL_MODULE :=", name)
 			fmt.Fprintln(w, "LOCAL_REQUIRED_MODULES := "+strings.Join(p.requiredModuleNames, " "))
 			fmt.Fprintln(w, "include $(BUILD_PHONY_PACKAGE)")
+		},
 	}
-	return
 }

python/androidmk.go

@@ -38,10 +38,12 @@ func (p *pythonBaseModule) subAndroidMk(data *android.AndroidMkData, obj interfa
 	}
 }
 
-func (p *pythonBaseModule) AndroidMk() (ret android.AndroidMkData, err error) {
+func (p *pythonBaseModule) AndroidMk() android.AndroidMkData {
+	ret := android.AndroidMkData{}
+
 	p.subAndroidMk(&ret, p.installer)
 
-	return ret, nil
+	return ret
 }
 
 func (p *pythonBinaryHostDecorator) AndroidMk(base *pythonBaseModule, ret *android.AndroidMkData) {