Remove unnecessary DeviceUsesClang.

This build function is unnecessary now that GCC is completely
unsupported for Android platform builds. It is similar to
USE_CLANG_PLATFORM_BUILD from the build/make side of things.

Bug: http://b/64032869
Test: Builds
Change-Id: Iddf5f91cc997c337c77a644265cb8dc4e5a915b4

android/config.go

@@ -430,13 +430,6 @@ func (c *config) DeviceName() string {
 	return *c.ProductVariables.DeviceName
 }
 
-func (c *config) DeviceUsesClang() bool {
-	if c.ProductVariables.DeviceUsesClang != nil {
-		return *c.ProductVariables.DeviceUsesClang
-	}
-	return true
-}
-
 func (c *config) ResourceOverlays() []string {
 	if c.ProductVariables.ResourceOverlays == nil {
 		return nil

android/variable.go

@@ -121,7 +121,6 @@ type productVariables struct {
 	DeviceArchVariant *string   `json:",omitempty"`
 	DeviceCpuVariant  *string   `json:",omitempty"`
 	DeviceAbi         *[]string `json:",omitempty"`
-	DeviceUsesClang   *bool     `json:",omitempty"`
 	DeviceVndkVersion *string   `json:",omitempty"`
 
 	DeviceSecondaryArch        *string   `json:",omitempty"`
@@ -231,7 +230,6 @@ func (v *productVariables) SetDefaultConfig() {
 		DeviceArchVariant:          stringPtr("armv8-a"),
 		DeviceCpuVariant:           stringPtr("generic"),
 		DeviceAbi:                  &[]string{"arm64-v8a"},
-		DeviceUsesClang:            boolPtr(true),
 		DeviceSecondaryArch:        stringPtr("arm"),
 		DeviceSecondaryArchVariant: stringPtr("armv8-a"),
 		DeviceSecondaryCpuVariant:  stringPtr("generic"),

cc/cc.go

@@ -947,13 +947,7 @@ func (c *Module) clang(ctx BaseModuleContext) bool {
 	clang := Bool(c.Properties.Clang)
 
 	if c.Properties.Clang == nil {
-		if ctx.Host() {
-			clang = true
-		}
-
-		if ctx.Device() && ctx.Config().DeviceUsesClang() {
-			clang = true
-		}
+		clang = true
 	}
 
 	if !c.toolchain(ctx).ClangSupported() {

scripts/build-ndk-prebuilts.sh

@@ -55,7 +55,6 @@ cat > ${SOONG_OUT}/soong.variables << EOF
     "DeviceAbi": [
         "arm64-v8a"
     ],
-    "DeviceUsesClang": true,
     "DeviceSecondaryArch": "arm",
     "DeviceSecondaryArchVariant": "armv7-a-neon",
     "DeviceSecondaryCpuVariant": "denver",