Re-enable JSWindowIDManagerTest.WindowID

ios/web/web_state/js/crw_js_window_id_manager_unittest.mm

Index: ios/web/web_state/js/crw_js_window_id_manager_unittest.mm
diff --git a/ios/web/public/web_state/js/crw_js_window_id_manager_unittest.mm b/ios/web/web_state/js/crw_js_window_id_manager_unittest.mm
similarity index 75%
rename from ios/web/public/web_state/js/crw_js_window_id_manager_unittest.mm
rename to ios/web/web_state/js/crw_js_window_id_manager_unittest.mm
index 4abc76abdda1b41e179327ff3ff3147262ec8a47..bc4280d3310290fb30cc10484eb312d97cad8b07 100644
--- a/ios/web/public/web_state/js/crw_js_window_id_manager_unittest.mm
+++ b/ios/web/web_state/js/crw_js_window_id_manager_unittest.mm
@@ -6,6 +6,7 @@
 
 #include "base/mac/scoped_nsobject.h"
 #import "ios/web/public/test/crw_test_js_injection_receiver.h"
+#import "ios/web/public/test/js_test_util.h"
 #include "ios/web/public/web_client.h"
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
@@ -33,19 +34,26 @@ class JSWindowIDManagerTest : public PlatformTest {
   web::WebClient web_client_;
 };
 
-// TODO(jyquinn): enable this test (crbug.com/465898).
-TEST_F(JSWindowIDManagerTest, DISABLED_WindowID) {
+// Tests that reinjection of window ID JS results in a different window ID.
+// TODO(ios): This test only works for the current implementation using
+// UIWebView. CRWTestJSInjectionReceiver should be re-written to eliminate
+// web view specificity (crbug.com/486840).
+TEST_F(JSWindowIDManagerTest, WindowIDReinjection) {
   EXPECT_TRUE(manager_.get());
   [manager_ inject];
   NSString* windowID = [manager_ windowId];
   EXPECT_EQ(32U, [windowID length]);
+  // Reset the __gCrWeb object to enable reinjection.
+  web::EvaluateJavaScriptAsString(manager_, @"__gCrWeb = undefined;");
   // Inject a second time to check that the ID is different.
   [manager_ inject];
   NSString* windowID2 = [manager_ windowId];
   EXPECT_FALSE([windowID isEqualToString:windowID2]);
 }
 
-TEST_F(JSWindowIDManagerTest, WindowIDDifferent) {
+// Tests that window ID injection by a second manager results in a different
+// window ID.
+TEST_F(JSWindowIDManagerTest, WindowIDDifferentManager) {
   [manager_ inject];
   NSString* windowID = [manager_ windowId];
   base::scoped_nsobject<CRWTestJSInjectionReceiver> receiver2(