Disable correctness CHECK() in RenderFrameImpl::OnDeleteFrame()

This CHECK is intended to catch when an IPC race around process shutdown
that leads to inconsistent state between the browser and the renderer.
Without the CHECK, there are likely instances where the bug is latent
but never triggered, so adding an explicit CHECK() likely increases the
number of overall crashes.

Due to how Android WebView crashes are attributed, and the fact that
Android seems to encounter this IPC race more, disable this CHECK()
there for now despite the fact that it doesn't actually fix anything...

Bug: 974173
Change-Id: I19bbbe0a0fdaffdc30cfdfbc1cf300d0de12839c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1740332Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685391}

content/renderer/render_frame_impl.cc

@@ -2536,7 +2536,11 @@ void RenderFrameImpl::OnDeleteFrame(FrameDeleteIntention intent) {
       // frame when a commit (and ownership transfer) is imminent.
       // TODO(dcheng): This is the case of https://crbug.com/838348.
       DCHECK(is_main_frame_);
+#if !defined(OS_ANDROID)
+      // This check is not enabled on Android, since it seems like it's much
+      // easier to trigger data races there.
       CHECK(!in_frame_tree_);
+#endif  // !defined(OS_ANDROID)
       break;
   }