Disable JsTranslateManagerTest.PerformancePlaceholder due to flakiness.

components/translate/ios/browser/js_translate_manager_unittest.mm

Index: components/translate/ios/browser/js_translate_manager_unittest.mm
diff --git a/components/translate/ios/browser/js_translate_manager_unittest.mm b/components/translate/ios/browser/js_translate_manager_unittest.mm
index 838a9f9bde527e1b11aeadeda885a2bdc654b431..21e9a9d8fb509040cc79ee37e5960d587f1221f2 100644
--- a/components/translate/ios/browser/js_translate_manager_unittest.mm
+++ b/components/translate/ios/browser/js_translate_manager_unittest.mm
@@ -47,7 +47,8 @@ class JsTranslateManagerTest : public PlatformTest {
   base::scoped_nsobject<JsTranslateManager> manager_;
 };
 
-TEST_F(JsTranslateManagerTest, PerformancePlaceholder) {
+// TODO(crbug.com/658619#c47): Test reported as flaky.
+TEST_F(JsTranslateManagerTest, DISABLED_PerformancePlaceholder) {
   [manager_ inject];
   EXPECT_TRUE(IsDefined(@"performance"));
   EXPECT_TRUE(IsDefined(@"performance.now"));