Sync change log from trunk.

ChangeLog

Index: ChangeLog
diff --git a/ChangeLog b/ChangeLog
index 2c0651d8da293053787d6cc4893b801cf3ea7fb4..8b751edd183bafd47c8fdff9e250ac450f1e2d2b 100644
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-2014-05-09: Sentinel
+2014-05-13: Sentinel
 
         The ChangeLog file is no longer maintained on bleeding_edge. This
         sentinel should stay on top of this list.
 
+2014-05-13: Version 3.27.2
+
+        Harden %SetIsObserved with RUNTIME_ASSERTs (Chromium issue 371782).
+
+        Drop unused static microtask API.
+
+        Introduce an api to query the microtask autorun state of an isolate.
+
+        Performance and stability improvements on all platforms.
+
+
+2014-05-12: Version 3.27.1
+
+        Object.observe: avoid accessing acceptList properties more than once
+        (issue 3315).
+
+        Array Iterator prototype should not have a constructor (issue 3293).
+
+        Fix typos in unit test for Array.prototype.fill().
+
+        Shorten autogenerated error message for functions only (issue 3019,
+        Chromium issue 331971).
+
+        Reland "Removed default Isolate." (Chromium issue 359977).
+
+        Performance and stability improvements on all platforms.
+
 
 2014-05-09: Version 3.27.0