Disable ExtensionToolbarModelTest.SizeAfterPrefChange.

chrome/browser/extensions/extension_toolbar_model_browsertest.cc

Index: chrome/browser/extensions/extension_toolbar_model_browsertest.cc
diff --git a/chrome/browser/extensions/extension_toolbar_model_browsertest.cc b/chrome/browser/extensions/extension_toolbar_model_browsertest.cc
index 6bce3aa673a064fdab1c2756312ebedd6b904d4a..7caba8d03163810d3e387bbf1cbd971dad1f9148 100644
--- a/chrome/browser/extensions/extension_toolbar_model_browsertest.cc
+++ b/chrome/browser/extensions/extension_toolbar_model_browsertest.cc
@@ -584,9 +584,13 @@ IN_PROC_BROWSER_TEST_F(ExtensionToolbarModelTest, HighlightModeAdd) {
   EXPECT_EQ(id_c, ExtensionAt(2)->id());
 }
 
-// Test is flaky (see crbug.com/379170), but currently enabled to gather traces.
-// If it fails, ping Finnur.
-IN_PROC_BROWSER_TEST_F(ExtensionToolbarModelTest, SizeAfterPrefChange) {
+// Test is flaky on Linus and ChromeOS, see crbug.com/379170.
+#if defined(OS_LINUX) || defined(OS_CHROMEOS)
+#define MAYBE_SizeAfterPrefChange DISABLED_SizeAfterPrefChange
+#else
+#define MAYBE_SizeAfterPrefChange SizeAfterPrefChange
+#endif
+IN_PROC_BROWSER_TEST_F(ExtensionToolbarModelTest, MAYBE_SizeAfterPrefChange) {
   // Load two extensions with browser action.
   base::FilePath extension_a_path(test_data_dir_.AppendASCII("api_test")
                                                 .AppendASCII("browser_action")