API functions returning Promises should not throw exceptions.

LayoutTests/fast/js/Promise-bindings-check-exception-expected.txt

+Operations that return a Promise type should handle exceptions by returning a rejected Promise with the exception.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+PASS Rejected as expected: no arguments
+PASS reason instanceof Error is true
+TypeError: Failed to execute 'promiseCheck' on 'Internals': 5 arguments required, but only 0 present.
+PASS Resolved as expected: valid arguments
+PASS Resolved as expected: convert(long)
+PASS Resolved as expected: convert(boolean)
+PASS Rejected as expected: type error(Dictionary)
+PASS reason instanceof Error is true
+TypeError: Failed to execute 'promiseCheck' on 'Internals': parameter 3 ('arg3') is not an object.
+PASS Resolved as expected: convert(String)
+PASS Rejected as expected: conversion error(toString)
+PASS reason instanceof Error is true
+Error: Thrown from toString
+PASS Rejected as expected: conversion error([String])
+PASS reason instanceof Error is true
+Error: Thrown from toString
+PASS Rejected as expected: rejected by the impl
+PASS reason instanceof Error is true
+InvalidStateError: Failed to execute 'promiseCheck' on 'Internals': Thrown from the native implementation.
+PASS Rejected as expected: no arguments
+PASS reason instanceof Error is true
+TypeError: Failed to execute 'promiseCheckWithoutExceptionState' on 'Internals': 2 arguments required, but only 0 present.
+PASS Resolved as expected: valid arguments
+PASS Resolved as expected: valid arguments
+PASS Rejected as expected: type error(Dictionary)
+PASS reason instanceof Error is true
+TypeError: Failed to execute 'promiseCheckWithoutExceptionState' on 'Internals': parameter 1 ('arg1') is not an object.
+PASS Resolved as expected: convert(String...)
+PASS Rejected as expected: conversion error(String...)
+PASS reason instanceof Error is true
+Error: Thrown from toString
+PASS Rejected as expected: range error(octet)
+PASS reason instanceof Error is true
+TypeError: Failed to execute 'promiseCheckRange' on 'Internals': Value is outside the 'octet' value range.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+