Keep a "sanitizer dependency" flag for each sanitizer.

This is so that we can avoid mutating state in sanitizerMutator, as
would be necessary if we only had a single bit for every sanitizer
together.

Test: Presubmits.
Change-Id: I5576367c12972fbea64342ab123118ec5a2cfeec
diff --git a/cc/linkable.go b/cc/linkable.go
index 6bec30c..04eab39 100644
--- a/cc/linkable.go
+++ b/cc/linkable.go
@@ -22,16 +22,16 @@
 	// than left undefined.
 	IsSanitizerExplicitlyDisabled(t SanitizerType) bool
 
-	// SanitizeDep returns the value of the SanitizeDep flag, which is set if a module is a dependency of a
-	// sanitized module.
-	SanitizeDep() bool
+	// SanitizeDep returns true if the module is statically linked into another that is sanitized
+	// with the given sanitizer.
+	SanitizeDep(t SanitizerType) bool
+
+	// SetSanitizeDep marks a module as a static dependency of another module to be sanitized.
+	SetSanitizeDep(t SanitizerType)
 
 	// SetSanitizer enables or disables the specified sanitizer type if it's supported, otherwise this should panic.
 	SetSanitizer(t SanitizerType, b bool)
 
-	// SetSanitizerDep returns true if the module is statically linked.
-	SetSanitizeDep(b bool)
-
 	// StaticallyLinked returns true if the module is statically linked.
 	StaticallyLinked() bool