PlzNavigate: checking post_id() in test PostInSubframe.

content/browser/frame_host/navigation_controller_impl_browsertest.cc

Index: content/browser/frame_host/navigation_controller_impl_browsertest.cc
diff --git a/content/browser/frame_host/navigation_controller_impl_browsertest.cc b/content/browser/frame_host/navigation_controller_impl_browsertest.cc
index 69510528ce3b68dcb152ff3e9f20960dadc4794d..db6deecf05b40ba85fbf6a58ff511424da894e12 100644
--- a/content/browser/frame_host/navigation_controller_impl_browsertest.cc
+++ b/content/browser/frame_host/navigation_controller_impl_browsertest.cc
@@ -5843,10 +5843,7 @@ IN_PROC_BROWSER_TEST_F(NavigationControllerBrowserTest,
     EXPECT_EQ("GET", root_entry->method());
     EXPECT_EQ(-1, root_entry->post_id());
     EXPECT_EQ("POST", frame_entry->method());
-    // TODO(clamy): Check the post id as well when PlzNavigate handles it
-    // properly.
-    if (!IsBrowserSideNavigationEnabled())
-      EXPECT_NE(-1, frame_entry->post_id());
+    EXPECT_NE(-1, frame_entry->post_id());
     EXPECT_FALSE(entry->GetHasPostData());
     EXPECT_EQ(-1, entry->GetPostID());
   }