Remove moduleContextImpl struct

The moduleContextImpl structure contains duplicate information on the
contexts. BaseModuleContext, ModuleContext and DepsContext can already
surface which Module is being processed via Module(). Because most of
the Rust-specific methods on the *Context structures simply forward to
the Module methods, expose a RustModule() method.

Test: cd external/rust/crates; mma
Change-Id: Ifee90825d54081fc5e9a8df0b7c4580412e9158c
diff --git a/rust/rust.go b/rust/rust.go
index 7b82b1f..1cc412d 100644
--- a/rust/rust.go
+++ b/rust/rust.go
@@ -506,39 +506,50 @@
 }
 
 type ModuleContextIntf interface {
+	RustModule() *Module
 	toolchain() config.Toolchain
-	baseModuleName() string
-	CrateName() string
-	nativeCoverage() bool
 }
 
 type depsContext struct {
 	android.BottomUpMutatorContext
-	moduleContextImpl
 }
 
 type moduleContext struct {
 	android.ModuleContext
-	moduleContextImpl
 }
 
-func (ctx *moduleContextImpl) nativeCoverage() bool {
-	return ctx.mod.nativeCoverage()
+type baseModuleContext struct {
+	android.BaseModuleContext
+}
+
+func (ctx *moduleContext) RustModule() *Module {
+	return ctx.Module().(*Module)
+}
+
+func (ctx *moduleContext) toolchain() config.Toolchain {
+	return ctx.RustModule().toolchain(ctx)
+}
+
+func (ctx *depsContext) RustModule() *Module {
+	return ctx.Module().(*Module)
+}
+
+func (ctx *depsContext) toolchain() config.Toolchain {
+	return ctx.RustModule().toolchain(ctx)
+}
+
+func (ctx *baseModuleContext) RustModule() *Module {
+	return ctx.Module().(*Module)
+}
+
+func (ctx *baseModuleContext) toolchain() config.Toolchain {
+	return ctx.RustModule().toolchain(ctx)
 }
 
 func (mod *Module) nativeCoverage() bool {
 	return mod.compiler != nil && mod.compiler.nativeCoverage()
 }
 
-type moduleContextImpl struct {
-	mod *Module
-	ctx BaseModuleContext
-}
-
-func (ctx *moduleContextImpl) toolchain() config.Toolchain {
-	return ctx.mod.toolchain(ctx.ctx)
-}
-
 func (mod *Module) toolchain(ctx android.BaseModuleContext) config.Toolchain {
 	if mod.cachedToolchain == nil {
 		mod.cachedToolchain = config.FindToolchain(ctx.Os(), ctx.Arch())
@@ -552,11 +563,7 @@
 func (mod *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 	ctx := &moduleContext{
 		ModuleContext: actx,
-		moduleContextImpl: moduleContextImpl{
-			mod: mod,
-		},
 	}
-	ctx.ctx = ctx
 
 	toolchain := mod.toolchain(ctx)
 
@@ -607,14 +614,6 @@
 
 }
 
-func (ctx *moduleContextImpl) baseModuleName() string {
-	return ctx.mod.ModuleBase.BaseModuleName()
-}
-
-func (ctx *moduleContextImpl) CrateName() string {
-	return ctx.mod.CrateName()
-}
-
 type dependencyTag struct {
 	blueprint.BaseDependencyTag
 	name       string
@@ -811,11 +810,7 @@
 func (mod *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 	ctx := &depsContext{
 		BottomUpMutatorContext: actx,
-		moduleContextImpl: moduleContextImpl{
-			mod: mod,
-		},
 	}
-	ctx.ctx = ctx
 
 	deps := mod.deps(ctx)
 	commonDepVariations := []blueprint.Variation{}
@@ -862,19 +857,10 @@
 	}
 }
 
-type baseModuleContext struct {
-	android.BaseModuleContext
-	moduleContextImpl
-}
-
 func (mod *Module) beginMutator(actx android.BottomUpMutatorContext) {
 	ctx := &baseModuleContext{
 		BaseModuleContext: actx,
-		moduleContextImpl: moduleContextImpl{
-			mod: mod,
-		},
 	}
-	ctx.ctx = ctx
 
 	mod.begin(ctx)
 }