--- a/testing/mochitest/mochitest_options.py
+++ b/testing/mochitest/mochitest_options.py
@@ -772,16 +772,21 @@ class MochitestArguments(ArgumentContain
 
         options.leakThresholds = {
             "default": options.defaultLeakThreshold,
             "tab": 10000,  # See dependencies of bug 1051230.
             # GMP rarely gets a log, but when it does, it leaks a little.
             "geckomediaplugin": 20000,
         }
 
+        # Bug 1293324 - OSX 10.10 sometimes leaks a little more
+        # graphics layers stuff in the content process.
+        if mozinfo.isMac:
+            options.leakThresholds["tab"] = 12000
+
         # XXX We can't normalize test_paths in the non build_obj case here,
         # because testRoot depends on the flavor, which is determined by the
         # mach command and therefore not finalized yet. Conversely, test paths
         # need to be normalized here for the mach case.
         if options.test_paths and build_obj:
             # Normalize test paths so they are relative to test root
             options.test_paths = [build_obj._wrap_path_argument(p).relpath()
                                   for p in options.test_paths]