Add NNAPI control flow

Bug: 136735929
Bug: 139181916
Test: m
Change-Id: I7a75175f00fc98df626c40ea669021ccd40130e0
diff --git a/neuralnetworks/1.3/IDevice.hal b/neuralnetworks/1.3/IDevice.hal
index 9afd778..8dc41f7 100644
--- a/neuralnetworks/1.3/IDevice.hal
+++ b/neuralnetworks/1.3/IDevice.hal
@@ -48,9 +48,14 @@
     /**
      * Gets the supported operations in a model.
      *
-     * getSupportedOperations indicates which operations of a model are fully
-     * supported by the vendor driver. If an operation may not be supported for
-     * any reason, getSupportedOperations must return false for that operation.
+     * getSupportedOperations indicates which operations of the top-level
+     * subgraph are fully supported by the vendor driver. If an operation may
+     * not be supported for any reason, getSupportedOperations must return
+     * false for that operation.
+     *
+     * The {@link OperationType::IF} and {@link OperationType::WHILE}
+     * operations may only be fully supported if the vendor driver fully
+     * supports all operations in the referenced subgraphs.
      *
      * @param model A model whose operations--and their corresponding operands--
      *     are to be verified by the driver.