Propagate push command line flag to the renderer process.

The renderer is using this to conditionally enable payload API surface
for incoming push messages, and thus needs to know about it.

This patch also re-enables the tests.

BUG=452666

Review URL: https://codereview.chromium.org/884093003

Cr-Commit-Position: refs/heads/master@{#313500}

chrome/browser/services/gcm/push_messaging_browsertest.cc

@@ -362,8 +362,7 @@ IN_PROC_BROWSER_TEST_F(PushMessagingBrowserTest, RegisterPersisted) {
   EXPECT_EQ(app_id_sw1.ToString(), gcm_service()->last_registered_app_id());
 }
 
-// Disabled due to failures: crbug.com/452666
-IN_PROC_BROWSER_TEST_F(PushMessagingBrowserTest, DISABLED_PushEventSuccess) {
+IN_PROC_BROWSER_TEST_F(PushMessagingBrowserTest, PushEventSuccess) {
   std::string script_result;
 
   TryToRegisterSuccessfully("1-0" /* expected_push_registration_id */);
@@ -466,9 +465,8 @@ IN_PROC_BROWSER_TEST_F(PushMessagingBrowserTest, PushEventNoPermission) {
 }
 
 #if defined(ENABLE_NOTIFICATIONS)
-// Disabled due to failures: crbug.com/452666
 IN_PROC_BROWSER_TEST_F(PushMessagingBrowserTest,
-                       DISABLED_PushEventEnforcesUserVisibleNotification) {
+                       PushEventEnforcesUserVisibleNotification) {
   std::string script_result;
 
   TryToRegisterSuccessfully("1-0" /* expected_push_registration_id */);

content/browser/renderer_host/render_process_host_impl.cc

@@ -1248,6 +1248,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableOverlayScrollbar,
     switches::kEnablePinch,
     switches::kEnablePreciseMemoryInfo,
+    switches::kEnablePushMessagePayload,
     switches::kEnableRendererMojoChannel,
     switches::kEnableSeccompFilterSandbox,
     switches::kEnableSkiaBenchmarking,