Lift BazelHandler interface into android/

Because it's commonly useful and not cc/ specific
Also export GenerateBazelBuildActions and update uses

Test: Existing tests pass
Change-Id: Ibc6858bb1129afba181a7686dda432defe33b00d

android/bazel_handler.go

@@ -57,6 +57,17 @@ type cqueryKey struct {
 	archType    ArchType
 }
 
+// bazelHandler is the interface for a helper object related to deferring to Bazel for
+// processing a module (during Bazel mixed builds). Individual module types should define
+// their own bazel handler if they support deferring to Bazel.
+type BazelHandler interface {
+	// Issue query to Bazel to retrieve information about Bazel's view of the current module.
+	// If Bazel returns this information, set module properties on the current module to reflect
+	// the returned information.
+	// Returns true if information was available from Bazel, false if bazel invocation still needs to occur.
+	GenerateBazelBuildActions(ctx ModuleContext, label string) bool
+}
+
 type BazelContext interface {
 	// The below methods involve queuing cquery requests to be later invoked
 	// by bazel. If any of these methods return (_, false), then the request