Remove extra basePath from ModuleSrcPath

ModuleSrcPath contains an embedded basePath as well as a
SoucePath that contains another basePath.  Remove the embedded
basePath, and make the SourcePath embedded.

Test: no change to build.ninja
Change-Id: I3cdf3477eca41ed35fac08a892aab22cbcdb2224
diff --git a/android/paths.go b/android/paths.go
index e76e1fe..8eabfb8 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -437,7 +437,7 @@
 func (p SourcePath) OverlayPath(ctx ModuleContext, path Path) OptionalPath {
 	var relDir string
 	if moduleSrcPath, ok := path.(ModuleSrcPath); ok {
-		relDir = moduleSrcPath.sourcePath.path
+		relDir = moduleSrcPath.path
 	} else if srcPath, ok := path.(SourcePath); ok {
 		relDir = srcPath.path
 	} else {
@@ -507,9 +507,7 @@
 
 // ModuleSrcPath is a Path representing a file rooted from a module's local source dir
 type ModuleSrcPath struct {
-	basePath
-	sourcePath SourcePath
-	moduleDir  string
+	SourcePath
 }
 
 var _ Path = ModuleSrcPath{}
@@ -521,7 +519,7 @@
 // module's local source directory.
 func PathForModuleSrc(ctx ModuleContext, paths ...string) ModuleSrcPath {
 	path := validatePath(ctx, paths...)
-	return ModuleSrcPath{basePath{path, ctx.AConfig()}, PathForSource(ctx, ctx.ModuleDir(), path), ctx.ModuleDir()}
+	return ModuleSrcPath{PathForSource(ctx, ctx.ModuleDir(), path)}
 }
 
 // OptionalPathForModuleSrc returns an OptionalPath. The OptionalPath contains a
@@ -533,16 +531,12 @@
 	return OptionalPathForPath(PathForModuleSrc(ctx, *p))
 }
 
-func (p ModuleSrcPath) String() string {
-	return p.sourcePath.String()
-}
-
 func (p ModuleSrcPath) genPathWithExt(ctx ModuleContext, subdir, ext string) ModuleGenPath {
-	return PathForModuleGen(ctx, subdir, p.moduleDir, pathtools.ReplaceExtension(p.path, ext))
+	return PathForModuleGen(ctx, subdir, pathtools.ReplaceExtension(p.path, ext))
 }
 
 func (p ModuleSrcPath) objPathWithExt(ctx ModuleContext, subdir, ext string) ModuleObjPath {
-	return PathForModuleObj(ctx, subdir, p.moduleDir, pathtools.ReplaceExtension(p.path, ext))
+	return PathForModuleObj(ctx, subdir, pathtools.ReplaceExtension(p.path, ext))
 }
 
 func (p ModuleSrcPath) resPathWithName(ctx ModuleContext, name string) ModuleResPath {