cc: export Stripper struct

The cc stripping logic can be reused for Rust. Export the Stripper
structure for that purpose. Extract the strip-related flags from
builderFlags into StripFlags. Add the method flagsToStripFlags
(similarly to flagsToBuilderFlags).

Add the helper method disableStripping on libraryDecorator.

Test: m
Bug: 153430439
Change-Id: I11aef1abb8d498a4c1672500a7398279edf7f548
diff --git a/cc/toolchain_library.go b/cc/toolchain_library.go
index 042e012..19f5ea4 100644
--- a/cc/toolchain_library.go
+++ b/cc/toolchain_library.go
@@ -36,8 +36,7 @@
 
 type toolchainLibraryDecorator struct {
 	*libraryDecorator
-
-	stripper
+	stripper Stripper
 
 	Properties toolchainLibraryProperties
 }
@@ -89,8 +88,8 @@
 	if library.stripper.StripProperties.Strip.Keep_symbols_list != nil {
 		fileName := ctx.ModuleName() + staticLibraryExtension
 		outputFile := android.PathForModuleOut(ctx, fileName)
-		buildFlags := flagsToBuilderFlags(flags)
-		library.stripper.stripStaticLib(ctx, srcPath, outputFile, buildFlags)
+		stripFlags := flagsToStripFlags(flags)
+		library.stripper.StripStaticLib(ctx, srcPath, outputFile, stripFlags)
 		return outputFile
 	}