Make java_sdk_library implement Dependency

dexpreopting boot jars is going to need to visit both java_library
and java_sdk_library modules.  Since java_sdk_library is already
a java_library module, move the SdkLibraryDependency methods out
of the way so that it will implement Dependency.  Also requries
re-ording some of the type switches to check for the more-specific
SdkLibraryDependency first.

Test: TestJavaSdkLibrary
Change-Id: I155c9ffaf31689dd150a4d99e07e432ff770b4a7
diff --git a/java/droiddoc.go b/java/droiddoc.go
index d893c09..cbe6be6 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -630,10 +630,10 @@
 			}
 		case libTag:
 			switch dep := module.(type) {
+			case SdkLibraryDependency:
+				deps.classpath = append(deps.classpath, dep.SdkImplementationJars(ctx, j.sdkVersion())...)
 			case Dependency:
 				deps.classpath = append(deps.classpath, dep.HeaderJars()...)
-			case SdkLibraryDependency:
-				deps.classpath = append(deps.classpath, dep.ImplementationJars(ctx, j.sdkVersion())...)
 			case android.SourceFileProducer:
 				checkProducesJars(ctx, dep)
 				deps.classpath = append(deps.classpath, dep.Srcs()...)
diff --git a/java/java.go b/java/java.go
index 3d7d6ad..2c7c1f6 100644
--- a/java/java.go
+++ b/java/java.go
@@ -338,8 +338,8 @@
 }
 
 type SdkLibraryDependency interface {
-	HeaderJars(ctx android.BaseContext, sdkVersion string) android.Paths
-	ImplementationJars(ctx android.BaseContext, sdkVersion string) android.Paths
+	SdkHeaderJars(ctx android.BaseContext, sdkVersion string) android.Paths
+	SdkImplementationJars(ctx android.BaseContext, sdkVersion string) android.Paths
 }
 
 type SrcDependency interface {
@@ -698,6 +698,15 @@
 			}
 		}
 		switch dep := module.(type) {
+		case SdkLibraryDependency:
+			switch tag {
+			case libTag:
+				deps.classpath = append(deps.classpath, dep.SdkHeaderJars(ctx, j.sdkVersion())...)
+				// names of sdk libs that are directly depended are exported
+				j.exportedSdkLibs = append(j.exportedSdkLibs, otherName)
+			default:
+				ctx.ModuleErrorf("dependency on java_sdk_library %q can only be in libs", otherName)
+			}
 		case Dependency:
 			switch tag {
 			case bootClasspathTag:
@@ -748,15 +757,6 @@
 			}
 
 			deps.aidlIncludeDirs = append(deps.aidlIncludeDirs, dep.AidlIncludeDirs()...)
-		case SdkLibraryDependency:
-			switch tag {
-			case libTag:
-				deps.classpath = append(deps.classpath, dep.HeaderJars(ctx, j.sdkVersion())...)
-				// names of sdk libs that are directly depended are exported
-				j.exportedSdkLibs = append(j.exportedSdkLibs, otherName)
-			default:
-				ctx.ModuleErrorf("dependency on java_sdk_library %q can only be in libs", otherName)
-			}
 		case android.SourceFileProducer:
 			switch tag {
 			case libTag:
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 1b0fe75..85ce533 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -145,6 +145,9 @@
 	testApiFilePath   android.Path
 }
 
+var _ Dependency = (*sdkLibrary)(nil)
+var _ SdkLibraryDependency = (*sdkLibrary)(nil)
+
 func (module *sdkLibrary) DepsMutator(ctx android.BottomUpMutatorContext) {
 	// Add dependencies to the stubs library
 	ctx.AddVariationDependencies(nil, publicApiStubsTag, module.stubsName(apiScopePublic))
@@ -596,7 +599,7 @@
 }
 
 // to satisfy SdkLibraryDependency interface
-func (module *sdkLibrary) HeaderJars(ctx android.BaseContext, sdkVersion string) android.Paths {
+func (module *sdkLibrary) SdkHeaderJars(ctx android.BaseContext, sdkVersion string) android.Paths {
 	// This module is just a wrapper for the stubs.
 	if ctx.Config().UnbundledBuildPrebuiltSdks() {
 		return module.PrebuiltJars(ctx, sdkVersion)
@@ -612,7 +615,7 @@
 }
 
 // to satisfy SdkLibraryDependency interface
-func (module *sdkLibrary) ImplementationJars(ctx android.BaseContext, sdkVersion string) android.Paths {
+func (module *sdkLibrary) SdkImplementationJars(ctx android.BaseContext, sdkVersion string) android.Paths {
 	// This module is just a wrapper for the stubs.
 	if ctx.Config().UnbundledBuildPrebuiltSdks() {
 		return module.PrebuiltJars(ctx, sdkVersion)