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

content/test/gpu/gpu_tests/screenshot_sync.py

Index: content/test/gpu/gpu_tests/screenshot_sync.py
diff --git a/content/test/gpu/gpu_tests/screenshot_sync.py b/content/test/gpu/gpu_tests/screenshot_sync.py
index e6984b9cd314ce665a2e95ecb2c5b375cd648ce4..b3881c0ee8db876321b2c22f376bea370b780afb 100644
--- a/content/test/gpu/gpu_tests/screenshot_sync.py
+++ b/content/test/gpu/gpu_tests/screenshot_sync.py
@@ -18,7 +18,10 @@ data_path = os.path.join(
 
 class ScreenshotSyncValidator(gpu_test_base.ValidatorBase):
   def CustomizeBrowserOptions(self, options):
-    options.AppendExtraBrowserArgs('--force-gpu-rasterization')
+    # --test-type=gpu is used only to suppress the "Google API Keys are missing"
+    # infobar, which causes flakiness in tests.
+    options.AppendExtraBrowserArgs(['--force-gpu-rasterization',
+                                    '--test-type=gpu'])
 
   def ValidateAndMeasurePage(self, page, tab, results):
     if not tab.screenshot_supported: