Remove old diagnostic code from CreateRenderView.

Now that we don't hit crashes from 575245 anymore, remove the
DumpWithoutCrashing and update the CHECK to prevent regression.

Bug: 575245
Change-Id: I9c66c870b978bd7db0e80f79703dd1c7864cc438
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1650148Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Commit-Queue: Charlie Reis <creis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667300}

content/browser/renderer_host/render_view_host_impl.cc

@@ -325,18 +325,12 @@ bool RenderViewHostImpl::CreateRenderView(
     return false;
   DCHECK(GetProcess()->IsInitializedAndNotDead());
   DCHECK(GetProcess()->GetBrowserContext());
-  CHECK(main_frame_routing_id_ != MSG_ROUTING_NONE ||
-        proxy_route_id != MSG_ROUTING_NONE);
-
-  // We should not set both main_frame_routing_id_ and proxy_route_id.  Log
-  // cases that this happens (without crashing) to track down
-  // https://crbug.com/575245.
-  // TODO(creis): Remove this once we've found the cause.
-  if (main_frame_routing_id_ != MSG_ROUTING_NONE &&
-      proxy_route_id != MSG_ROUTING_NONE) {
-    NOTREACHED() << "Don't set both main_frame_routing_id_ and proxy_route_id";
-    base::debug::DumpWithoutCrashing();
-  }
+
+  // Exactly one of main_frame_routing_id_ or proxy_route_id should be set.
+  CHECK((main_frame_routing_id_ != MSG_ROUTING_NONE &&
+         proxy_route_id == MSG_ROUTING_NONE) ||
+        (main_frame_routing_id_ == MSG_ROUTING_NONE &&
+         proxy_route_id != MSG_ROUTING_NONE));
 
   RenderFrameHostImpl* main_rfh = nullptr;
   if (main_frame_routing_id_ != MSG_ROUTING_NONE) {