Bug 765599:  Make CSS insertRule methods throw SYNTAX_ERR when given an empty rule or more than one rule.  r=bzbarsky

This implements the proposed spec clarification in
http://lists.w3.org/Archives/Public/www-style/2013Feb/0229.html which
makes us compatible with WebKit on the insertRule tests in this patch.

I confirmed that the test reports 7 failures without the patch, but
passes with the patch.  (I'm a little disturbed by the way our
testharness.js integration elides runs of successive passes.)
Bug 838407 - aria-hidden false value shouldn't be exposed via object attributes, r=tbsaunde
No bug - Include missing header in mfbt/ASan.h. r=me
Bug 836349: Remove ICE state check from get*Description r=ekr
Bug 831290 - Avoid double done_cb firing in nICEr r=abr
Merge the last PGO-green inbound changeset to m-c
Bug 842128 - Don't call nsLayoutUtils::GetFontMetricsForFrame in nsProgressFrame::ComputeAutoSize. r=dbaron.
Bug 835381 - Update libnestegg to 38c83d9d4c0c5c84373aa285bd30094a12d6b6f6. r=kinetik
Bug 835381 - Use the new libnestegg API to sniff for WebM. r=kinetik
Bug 835381 - Unit tests for the MediaSniffer to make sure Matroska files are not sniffed as WebM. r=kinetik
Bug 841802 - Part 1: Add ErrorResult::ClearMessage(). r=bz
Bug 841802 - Part 2: Use TextDecoderBase from nsContentUtils::ConvertStringFromCharset(). r=hsivonen
Bug 835381 - Add the new symbol to the symbol list for libnestegg.
Bug 842463 - Prevent crash when feImage is not in a document. r=dzbarsky.
Bug 757188 - Refactor FlowGraphSummary; r=jorendorff
Bug 842346 - Fennec doesn't build with Java 7 because of JavaAddonManager. r=kats
Bug 841811 - Remove deprecated enablePrivilege from test added in bug 790475. r=ehsan.
Bug 568593 - Refactor ModuleBox; r=jorendorff
Bug 828778 put icon in manifest so we can show provider icons in activation panel, r=gavin
Bug 777712 - Adding file descriptors leaks logging on web-workers-shutdown. r=yoric