Fix RenderFrameHostChanged WebContentsObserver methods

content/public/test/web_contents_observer_sanity_checker.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/public/test/web_contents_observer_sanity_checker.h"
 
-#include "base/debug/stack_trace.h"
 #include "base/strings/stringprintf.h"
 #include "content/common/frame_messages.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 
@@ skipping 55 matching lines @@
     RenderFrameHost* render_frame_host) {
   // TODO(nick): Record this.
 }
 
 void WebContentsObserverSanityChecker::RenderFrameHostChanged(
     RenderFrameHost* old_host,
     RenderFrameHost* new_host) {
   CHECK(new_host);
   CHECK_NE(new_host, old_host);
 
-  // TODO(nasko): Implement consistency checking for RenderFrameHostChanged
-  // in follow up CL.
+  if (old_host) {
+    std::pair<int, int> routing_pair =
+        std::make_pair(old_host->GetProcess()->GetID(),
+                       old_host->GetRoutingID());
+    bool old_did_exist = !!current_hosts_.erase(routing_pair);
+    if (!old_did_exist) {
+      CHECK(false)
+          << "RenderFrameHostChanged called with old host that did not exist:"
+          << Format(old_host);
+    }
+  }
+
+  std::pair<int, int> routing_pair =
+      std::make_pair(new_host->GetProcess()->GetID(),
+                     new_host->GetRoutingID());
+  bool host_exists = !current_hosts_.insert(routing_pair).second;
+  if (host_exists) {
+    CHECK(false)
+        << "RenderFrameHostChanged called more than once for routing pair:"
+        << Format(new_host);
+  }
 }
 
 void WebContentsObserverSanityChecker::FrameDeleted(
     RenderFrameHost* render_frame_host) {
   // A frame can be deleted before RenderFrame in the renderer process is
   // created, so there is not much that can be enforced here.
   CHECK(!web_contents_destroyed_);
 }
 
 void WebContentsObserverSanityChecker::DidStartProvisionalLoadForFrame(
@@ skipping 135 matching lines @@
 
 std::string WebContentsObserverSanityChecker::Format(
     RenderFrameHost* render_frame_host) {
   return base::StringPrintf(
       "(%d, %d -> %s)", render_frame_host->GetProcess()->GetID(),
       render_frame_host->GetRoutingID(),
       render_frame_host->GetSiteInstance()->GetSiteURL().spec().c_str());
 }
 
 }  // namespace content