BaseCompilerProperties: add AidlInterface struct for aidl_interface info

This is necessary for cc_cmake_snapshot to snapshot and generate build
rules for actual source files (AIDL files) and not generated cpp
sources. Otherwise, this information is inaccessible for cc module after
aidl_interface pass.

Bug: 302718225
Test: Build aosp/2798713
Change-Id: I991e73f74d7551d21f337a7161cce55ba51fec71

cc/compiler.go

@@ -141,6 +141,19 @@ type BaseCompilerProperties struct {
 		Flags []string
 	}
 
+	// Populated by aidl_interface CPP backend to let other modules (e.g. cc_cmake_snapshot)
+	// access actual source files and not generated cpp intermediary sources.
+	AidlInterface struct {
+		// list of aidl_interface sources
+		Sources []string `blueprint:"mutated"`
+
+		// AIDL backend language (e.g. "cpp", "ndk")
+		Lang string `blueprint:"mutated"`
+
+		// list of flags passed to AIDL generator
+		Flags []string `blueprint:"mutated"`
+	} `blueprint:"mutated"`
+
 	Renderscript struct {
 		// list of directories that will be added to the llvm-rs-cc include paths
 		Include_dirs []string