Add "--test-type=gpu" to suppress API Keys InfoBar

content/test/gpu/gpu_tests/gpu_rasterization.py

Index: content/test/gpu/gpu_tests/gpu_rasterization.py
diff --git a/content/test/gpu/gpu_tests/gpu_rasterization.py b/content/test/gpu/gpu_tests/gpu_rasterization.py
index 68f4e60113f01e48b86d5724c43302af540ba535..a2e5e83515c0449b76504ff2cc85721bb6d199e0 100644
--- a/content/test/gpu/gpu_tests/gpu_rasterization.py
+++ b/content/test/gpu/gpu_tests/gpu_rasterization.py
@@ -32,10 +32,13 @@ def _DidTestSucceed(tab):
 
 class GpuRasterizationValidator(cloud_storage_test_base.ValidatorBase):
   def CustomizeBrowserOptions(self, options):
+    # --test-type=gpu is used only to suppress the "Google API Keys are missing"
+    # infobar, which causes flakiness in tests.
     options.AppendExtraBrowserArgs(['--enable-threaded-compositing',
                                     '--enable-impl-side-painting',
                                     '--force-gpu-rasterization',
-                                    '--enable-gpu-benchmarking'])
+                                    '--enable-gpu-benchmarking',
+                                    '--test-type=gpu'])
 
   def ValidateAndMeasurePage(self, page, tab, results):
     if not _DidTestSucceed(tab):