Reverting half the checkins that are suspected of breaking the world.

Reverting half the checkins that are suspected of breaking the world.

Revert 114384 - Var keeps invalid var_id if VarTracker release it and there is
another reference.

When VarTracker remove PP_Var from VarMap, it release its Var object
if needed, but never reset var_id stored in Var object. Then, if Var's
reference count is not 1, Var continue to exist with invalid var_id until
the last reference is released.

BUG=87310
TEST=ui_tests --gtest_filter='PPAPITest.WebSocket_*'

Review URL: http://codereview.chromium.org/8872065

TBR=toyoshim@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=114398

[Takashi Toyoshima, 2011-12-14 12:59:39]

LGTM.
This change must break the waterfall because RsetVarID() which I added
cause an unexpected DCHECK failure.
I must notice this problem before landing.
Sorry for inconvenience and thank you for handling this revert.