Revert of Tests that the title only ever gets replaced for the current page....

Revert of Tests that the title only ever gets replaced for the current page. (patchset #2 id:20001 of https://codereview.chromium.org/1137773003/)

Reason for revert:
We're seeing crashes; this looks to be the wrong approach.

Original issue's description:
> Tests that the title only ever gets replaced for the current page.
>
> BUG=369661
> TEST=All tests remain green.
>
> Committed: https://crrev.com/e5fab09f6e313f78d4113e4d4fe0ce3b38ce0ca5
> Cr-Commit-Position: refs/heads/master@{#329414}

TBR=creis@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=369661

Review URL: https://codereview.chromium.org/1144443005

Cr-Commit-Position: refs/heads/master@{#329686}

content/browser/web_contents/web_contents_impl.cc

@@ -3870,11 +3870,6 @@ void WebContentsImpl::UpdateTitle(RenderFrameHost* render_frame_host,
   NavigationEntryImpl* entry = controller_.GetEntryWithPageID(
       rvh->GetSiteInstance(), page_id);
 
-  // Re http://crbug.com/369661, page id is going away. This function should
-  // only ever be called for the last committed entry. When this is verified,
-  // this function can be greatly simplified.
-  CHECK_EQ(entry, controller_.GetLastCommittedEntry());
-
   // We can handle title updates when we don't have an entry in
   // UpdateTitleForEntry, but only if the update is from the current RVH.
   // TODO(avi): Change to make decisions based on the RenderFrameHost.