Tentatively enable flaky GpuCrash.GPUProcessCrashesExactlyOnce again.

content/test/gpu/gpu_tests/context_lost_expectations.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from gpu_tests.gpu_test_expectations import GpuTestExpectations
 
 # See the GpuTestExpectations class for documentation.
 
 class ContextLostExpectations(GpuTestExpectations):
   def SetExpectations(self):
@@ skipping 13 matching lines @@
     self.Skip('ContextLost.WebGLContextLostFromSelectElement',
               ['win8', 'nvidia'], bug=524808)
 
     # Flaky on Mac 10.7 and 10.8 resulting in crashes during browser
     # startup, so skip this test in those configurations.
     self.Skip('ContextLost.WebGLContextLostFromSelectElement',
               ['mountainlion', 'debug'], bug=497411)
     self.Skip('ContextLost.WebGLContextLostFromSelectElement',
               ['lion', 'debug'], bug=498149)
 
-    # Flaky on linux_chromium_rel_ng and mac_chromium_rel_ng bots.
-    self.Flaky('GpuCrash.GPUProcessCrashesExactlyOnce',
-               ['linux'], bug=608923)
-    self.Flaky('GpuCrash.GPUProcessCrashesExactlyOnce',
-               ['mac'], bug=608923)
-
     # 'Browser must support tab control' raised on Android
     self.Fail('GpuCrash.GPUProcessCrashesExactlyOnce',
               ['android'], bug=609629)
     self.Fail('ContextLost.WebGLContextLostFromGPUProcessExit',
               ['android'], bug=609629)
     self.Fail('ContextLost.WebGLContextLostInHiddenTab',
               ['android'], bug=609629)