Implement suspend() and resume() for OfflineAudioContext

LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt

Index: LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
diff --git a/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt b/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
index 4796efb8af90a64e8ea3bc311476d6366809e6f0..1365bcb07c0e99b44a70872b43ebb6054a3100cc 100644
--- a/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
+++ b/LayoutTests/webaudio/audiocontext-suspend-resume-expected.txt
@@ -7,15 +7,15 @@ PASS offlineContext = new OfflineAudioContext(1, durationInSeconds * sampleRate,
 PASS offlineContext.state is "suspended"
 PASS p1 = offlineContext.suspend() did not throw exception.
 PASS [object Promise] is an instance of function Promise() { [native code] }
-PASS offlineContext.suspend() was correctly rejected: InvalidAccessError: cannot suspend an OfflineAudioContext
+PASS offlineContext.suspend() was correctly rejected: TypeError: Failed to execute 'suspend' on 'OfflineAudioContext': 1 argument required, but only 0 present.
 PASS p2 = offlineContext.resume() did not throw exception.
 PASS [object Promise] is an instance of function Promise() { [native code] }
 PASS offlineContext.state is "suspended"
-PASS offlineContext.resume() was correctly rejected: InvalidAccessError: cannot resume an OfflineAudioContext
+PASS offlineContext.resume() was correctly rejected: InvalidStateError: cannot resume the context is already running or has not started
 PASS p3 = offlineContext.startRendering() did not throw exception.
 PASS offlineContext.state is "closed"
-PASS offlineContext.suspend() on a closed context rejected: InvalidAccessError: cannot suspend an OfflineAudioContext
-PASS offlineContext.resume() on a closed context rejected: InvalidAccessError: cannot resume an OfflineAudioContext
+PASS offlineContext.suspend() on a closed context rejected: InvalidStateError: cannot schedule a suspend in the past, beyond the total render duration or at the duplicate position.

[Raymond Toy, 2015/05/28 16:37:34]

It would be nice if three different messages were sent with some information
about suspend time, the current time (or render length).

If we do, we need to think about whether the quantized time is used or the
requested time. (Probably both?)

[hongchan, 2015/06/09 20:49:58]

Good idea. I will try to be more specific on these error messages.

+PASS offlineContext.resume() on a closed context rejected: InvalidStateError: cannot resume the context is already running or has not started
 PASS successfullyParsed is true
 
 TEST COMPLETE