Make error message more precise.

Bug: 132357300
Test: m nothing
Change-Id: Iaac6aaf61a3bbf8476f0b11cf2c01d7d96a79920

dexpreopt/class_loader_context.go

@@ -437,7 +437,11 @@ func validateClassLoaderContextRec(sdkVer int, clcs []*ClassLoaderContext) (bool
 			if sdkVer == AnySdkVersion {
 				// Return error if dexpreopt doesn't know paths to one of the <uses-library>
 				// dependencies. In the future we may need to relax this and just disable dexpreopt.
-				return false, fmt.Errorf("invalid path for <uses-library> \"%s\"", clc.Name)
+				if clc.Host == nil {
+					return false, fmt.Errorf("invalid build path for <uses-library> \"%s\"", clc.Name)
+				} else {
+					return false, fmt.Errorf("invalid install path for <uses-library> \"%s\"", clc.Name)
+				}
 			} else {
 				// No error for compatibility libraries, as Soong doesn't know if they are needed
 				// (this depends on the targetSdkVersion in the manifest), but the CLC is invalid.

dexpreopt/class_loader_context_test.go

@@ -195,7 +195,7 @@ func TestCLCMaybeAdd(t *testing.T) {
 	// But class loader context in such cases should raise an error on validation.
 	t.Run("validate", func(t *testing.T) {
 		_, err := validateClassLoaderContext(m)
-		checkError(t, err, "invalid path for <uses-library> \"a\"")
+		checkError(t, err, "invalid build path for <uses-library> \"a\"")
 	})
 }