Instead of enqueueing SPDY frames, enqueue SPDY streams that are ready to produce data.

Instead of enqueueing SPDY frames, enqueue SPDY streams that are ready to produce data. This allows us to lazily allocate a stream id.

The second CL was reverted because of use-after-free problems.  Producers were deleted before they were pop()'d from the WriteQueue, which turns out to be a no-no.  This version fixes this defect.

The initial CL was reverted because of memory leaks.  Both SpdyIOBufferProducers leaked the SpdyFrame they owned.  The second version of the CL fixes this defect.

Attempting to re-land 144649

Revert 147692 - Revert 144655 - Revert 144649

BUG=111708
TEST=net_unittests


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=148660

[Ryan Hamilton, 2012-07-26 19:54:15]

willchan: PTAL.  Patch set 1 is the original CL.  You can do a diff of patch set
12 (the most recent) to patch set 1 to see the effective changes.

[willchan no longer on Chromium, 2012-07-26 20:37:16]

lgtm

[commit-bot: I haz the power, 2012-07-26 20:39:23]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rch@chromium.org/10815074/20001

[commit-bot: I haz the power, 2012-07-26 23:53:22]

Change committed as 148660