Add set of workarounds allowed to be different between browser and GPU.

content/test/gpu/page_sets/gpu_process_tests.py

Index: content/test/gpu/page_sets/gpu_process_tests.py
diff --git a/content/test/gpu/page_sets/gpu_process_tests.py b/content/test/gpu/page_sets/gpu_process_tests.py
index fcf2f930be476860fc97f2d7605a6df482713773..9d59b45562ddd5ef73c71d919ba5a2cbcbb8ec0e 100644
--- a/content/test/gpu/page_sets/gpu_process_tests.py
+++ b/content/test/gpu/page_sets/gpu_process_tests.py
@@ -7,6 +7,13 @@ from telemetry.page import page_test
 
 from gpu_tests import gpu_test_base
 
+
+# A list of exceptional driver bug workarounds allowed to be present
+# during some of the tests that ensure that the browser's and GPU
+# process's notions of the driver bug workarounds are equivalent.
+workaround_exceptions = set([u'decode_encode_srgb_for_generatemipmap'])
+
+
 class GpuProcessSharedPageState(gpu_test_base.GpuSharedPageState):
 
   gpu_switches = ['--gpu-no-complete-info-collection',
@@ -145,7 +152,7 @@ class EqualBugWorkaroundsBasePage(gpu_test_base.PageBase):
       'chrome.gpuBenchmarking.getGpuDriverBugWorkarounds()')
 
     diff = set(browser_list).symmetric_difference(set(gpu_list))
-    if len(diff) > 0:
+    if not diff.issubset(workaround_exceptions):
       print 'Test failed. Printing page contents:'
       print tab.EvaluateJavaScript('document.body.innerHTML')
       raise page_test.Failure('Browser and GPU process list of driver bug' \
@@ -703,7 +710,7 @@ class OnlyOneWorkaroundPage(EqualBugWorkaroundsBasePage):
     gpu_list, disabled_gl_extensions = recorded_info
 
     diff = set(self.expected_workarounds).symmetric_difference(set(gpu_list))
-    if len(diff) > 0:
+    if not diff.issubset(workaround_exceptions):
       print 'Test failed. Printing page contents:'
       print tab.EvaluateJavaScript('document.body.innerHTML')
       raise page_test.Failure('GPU process and expected list of driver bug' \