Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index 1f6101d375b5172ea843a7e52505c5285766a6aa..e4c7fd7f0eb44e0417a87ccb26a498e45084f89e 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -30,7 +30,6 @@
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/site_instance_impl.h"
 #include "content/browser/webui/web_ui_controller_factory_registry.h"
-#include "content/browser/webui/web_ui_impl.h"
 #include "content/common/frame_messages.h"
 #include "content/common/site_isolation_policy.h"
 #include "content/common/view_messages.h"
@@ -39,7 +38,6 @@
 #include "content/public/browser/render_widget_host_iterator.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/user_metrics.h"
-#include "content/public/browser/web_ui_controller.h"
 #include "content/public/common/browser_plugin_guest_mode.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/referrer.h"
@@ -220,7 +218,7 @@ RenderFrameHostManager::RenderFrameHostManager(
       render_widget_delegate_(render_widget_delegate),
       proxy_hosts_(new RenderFrameProxyHostMap(this)),
       interstitial_page_(nullptr),
-      should_reuse_web_ui_(false),
+      current_web_ui_is_navigating_(false),
       weak_factory_(this) {
   DCHECK(frame_tree_node_);
 }
@@ -245,10 +243,6 @@ RenderFrameHostManager::~RenderFrameHostManager() {
   // the current RenderFrameHost and uses it during its destructor.
   ResetProxyHosts();
 
-  // Release the WebUI prior to resetting the current RenderFrameHost, as the
-  // WebUI accesses the RenderFrameHost during cleanup.
-  web_ui_.reset();
-
   // We should always have a current RenderFrameHost except in some tests.
   SetRenderFrameHost(scoped_ptr<RenderFrameHostImpl>());
 }
@@ -289,6 +283,21 @@ RenderViewHostImpl* RenderFrameHostManager::pending_render_view_host() const {
   return pending_render_frame_host_->render_view_host();
 }
 
+WebUIImpl* RenderFrameHostManager::GetNavigatingWebUI() const {
+  if (current_web_ui_is_navigating_)
+    return render_frame_host_->web_ui();
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation)) {
+    if (speculative_render_frame_host_)
+      return speculative_render_frame_host_->web_ui();
+  } else {
+    if (pending_render_frame_host_)
+      return pending_render_frame_host_->web_ui();
+  }
+  return nullptr;
+}
+
 RenderWidgetHostView* RenderFrameHostManager::GetRenderWidgetHostView() const {
   if (interstitial_page_)
     return interstitial_page_->GetView();
@@ -357,27 +366,6 @@ void RenderFrameHostManager::RemoveOuterDelegateFrame() {
       outer_delegate_frame_tree_node);
 }
 
-void RenderFrameHostManager::SetPendingWebUI(const GURL& url, int bindings) {
-  pending_web_ui_ = CreateWebUI(url, bindings);
-  pending_and_current_web_ui_.reset();
-}
-
-scoped_ptr<WebUIImpl> RenderFrameHostManager::CreateWebUI(const GURL& url,
-                                                          int bindings) {
-  scoped_ptr<WebUIImpl> new_web_ui(delegate_->CreateWebUIForRenderManager(url));
-
-  // If we have assigned (zero or more) bindings to this NavigationEntry in the
-  // past, make sure we're not granting it different bindings than it had
-  // before.  If so, note it and don't give it any bindings, to avoid a
-  // potential privilege escalation.
-  if (new_web_ui && bindings != NavigationEntryImpl::kInvalidBindings &&
-      new_web_ui->GetBindings() != bindings) {
-    RecordAction(base::UserMetricsAction("ProcessSwapBindingsMismatch_RVHM"));
-    return nullptr;
-  }
-  return new_web_ui.Pass();
-}
-
 RenderFrameHostImpl* RenderFrameHostManager::Navigate(
     const GURL& dest_url,
     const FrameNavigationEntry& frame_entry,
@@ -426,6 +414,11 @@ RenderFrameHostImpl* RenderFrameHostManager::Navigate(
     if (!InitRenderView(dest_render_frame_host->render_view_host(), nullptr))
       return nullptr;
 
+    if (GetNavigatingWebUI()) {
+      GetNavigatingWebUI()->RenderViewCreated(
+          dest_render_frame_host->render_view_host());
+    }
+
     // Now that we've created a new renderer, be sure to hide it if it isn't
     // our primary one.  Otherwise, we might crash if we try to call Show()
     // on it later.
@@ -676,13 +669,14 @@ void RenderFrameHostManager::CommitPendingIfNecessary(
     RenderFrameHostImpl* render_frame_host,
     bool was_caused_by_user_gesture) {
   if (!pending_render_frame_host_ && !speculative_render_frame_host_) {
-    DCHECK(!should_reuse_web_ui_ || web_ui_);
+    DCHECK(!current_web_ui_is_navigating_ || render_frame_host_->web_ui());
 
     // We should only hear this from our current renderer.
     DCHECK_EQ(render_frame_host_, render_frame_host);
 
-    // Even when there is no pending RVH, there may be a pending Web UI.
-    if (pending_web_ui() || speculative_web_ui_)
+    // A commit is required if there is a navigating WebUI, even without a
+    // pending or speculative RenderFrameHost.
+    if (GetNavigatingWebUI())
       CommitPending();
     return;
   }
@@ -1025,41 +1019,44 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
       (!request.browser_initiated() && is_main_frame) ||
       (!is_main_frame && !dest_site_instance->RequiresDedicatedProcess() &&
        !current_site_instance->RequiresDedicatedProcess())) {
-    // Reuse the current RFH if its SiteInstance matches the the navigation's
-    // or if this is a subframe navigation. We only swap RFHs for subframes when
-    // --site-per-process is enabled.
+    // Reuse the current RenderFrameHost if its SiteInstance matches the the
+    // navigation's or if this is a subframe navigation. We only swap RFHs for
+    // subframes when --site-per-process is enabled.
     CleanUpNavigation();
     navigation_rfh = render_frame_host_.get();
 
-    // As SiteInstances are the same, check if the WebUI should be reused.
-    const NavigationEntry* current_navigation_entry =
-        delegate_->GetLastCommittedNavigationEntryForRenderManager();
-    should_reuse_web_ui_ = ShouldReuseWebUI(current_navigation_entry,
-                                            request.common_params().url);
-    if (!should_reuse_web_ui_) {
-      speculative_web_ui_ = CreateWebUI(request.common_params().url,
-                                        request.bindings());
-      // Make sure the current RenderViewHost has the right bindings.
-      if (speculative_web_ui() &&
-          !render_frame_host_->GetProcess()->IsForGuestsOnly()) {
-        render_frame_host_->render_view_host()->AllowBindings(
-            speculative_web_ui()->GetBindings());
-      }
-    }
+    UpdateWebUIOnCurrentFrameHost(
+        request.common_params().url,
+        request.restore_type() != NavigationEntryImpl::RESTORE_NONE,
+        request.bindings());
+
+    DCHECK(!speculative_render_frame_host_);
   } else {
-    // If the SiteInstance for the final URL doesn't match the one from the
-    // speculatively created RenderFrameHost, create a new RenderFrameHost using
-    // this new SiteInstance.
+    // If the current RenderFrameHost cannot be used a new speculative one is
+    // created with the SiteInstance for the current URL.
+
+    // Check if an existing speculative RenderFrameHost can be reused.
     if (!speculative_render_frame_host_ ||
         speculative_render_frame_host_->GetSiteInstance() !=
             dest_site_instance.get()) {
+      // If a previous speculative RenderFrameHost didn't exist or if its
+      // SiteInstace differs from the one for the current URL, a new one needs
+      // to be created.
       CleanUpNavigation();
-      bool success = CreateSpeculativeRenderFrameHost(
-          request.common_params().url, current_site_instance,
-          dest_site_instance.get(), request.bindings());
+      bool success = CreateSpeculativeRenderFrameHost(current_site_instance,
+                                                      dest_site_instance.get());
       DCHECK(success);
     }
+
+    bool changed_web_ui = speculative_render_frame_host_->UpdateWebUI(
+        request.common_params().url, request.bindings());
+    if (changed_web_ui && speculative_render_frame_host_->web_ui()) {
+      speculative_render_frame_host_->web_ui()->RenderViewCreated(
+          speculative_render_frame_host_->render_view_host());
+    }
     DCHECK(speculative_render_frame_host_);
+    DCHECK_EQ(GetNavigatingWebUI(), speculative_render_frame_host_->web_ui());
+
     navigation_rfh = speculative_render_frame_host_.get();
 
     // Check if our current RFH is live.
@@ -1071,6 +1068,7 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
       // RFH isn't live.)
       CommitPending();
     }
+    DCHECK(!current_web_ui_is_navigating_);
   }
   DCHECK(navigation_rfh &&
          (navigation_rfh == render_frame_host_.get() ||
@@ -1081,8 +1079,12 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
   if (!navigation_rfh->IsRenderFrameLive()) {
     // Recreate the opener chain.
     CreateOpenerProxies(navigation_rfh->GetSiteInstance(), frame_tree_node_);
-    if (!InitRenderView(navigation_rfh->render_view_host(), nullptr)) {
+    if (!InitRenderView(navigation_rfh->render_view_host(), nullptr))
       return nullptr;
+
+    if (GetNavigatingWebUI()) {
+      GetNavigatingWebUI()->RenderViewCreated(
+          navigation_rfh->render_view_host());
     }
 
     if (navigation_rfh == render_frame_host_) {
@@ -1104,8 +1106,9 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
 void RenderFrameHostManager::CleanUpNavigation() {
   CHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableBrowserSideNavigation));
-  speculative_web_ui_.reset();
-  should_reuse_web_ui_ = false;
+  // TODO(carlosk): the discarding of the current RFH WebUI and the cleanup of
+  // the speculative RFH should not always happen together.
+  current_web_ui_is_navigating_ = false;
   if (speculative_render_frame_host_)
     DiscardUnusedFrame(UnsetSpeculativeRenderFrameHost());
 }
@@ -1298,18 +1301,6 @@ bool RenderFrameHostManager::ShouldSwapBrowsingInstancesForNavigation(
   return false;
 }
 
-bool RenderFrameHostManager::ShouldReuseWebUI(
-    const NavigationEntry* current_entry,
-    const GURL& new_url) const {
-  NavigationControllerImpl& controller =
-      delegate_->GetControllerForRenderManager();
-  return current_entry && web_ui_ &&
-      (WebUIControllerFactoryRegistry::GetInstance()->GetWebUIType(
-          controller.GetBrowserContext(), current_entry->GetURL()) ==
-       WebUIControllerFactoryRegistry::GetInstance()->GetWebUIType(
-          controller.GetBrowserContext(), new_url));
-}
-
 SiteInstance* RenderFrameHostManager::GetSiteInstanceForNavigation(
     const GURL& dest_url,
     SiteInstance* source_instance,
@@ -1642,8 +1633,8 @@ void RenderFrameHostManager::CreatePendingRenderFrameHost(
   CreateProxiesForNewRenderFrameHost(old_instance, new_instance);
 
   // Create a non-swapped-out RFH with the given opener.
-  pending_render_frame_host_ = CreateRenderFrame(
-      new_instance, pending_web_ui(), create_render_frame_flags, nullptr);
+  pending_render_frame_host_ =
+      CreateRenderFrame(new_instance, create_render_frame_flags, nullptr);
 }
 
 void RenderFrameHostManager::CreateProxiesForNewRenderFrameHost(
@@ -1739,18 +1730,11 @@ scoped_ptr<RenderFrameHostImpl> RenderFrameHostManager::CreateRenderFrameHost(
 
 // PlzNavigate
 bool RenderFrameHostManager::CreateSpeculativeRenderFrameHost(
-    const GURL& url,
     SiteInstance* old_instance,
-    SiteInstance* new_instance,
-    int bindings) {
+    SiteInstance* new_instance) {
   CHECK(new_instance);
   CHECK_NE(old_instance, new_instance);
-  CHECK(!should_reuse_web_ui_);
-
-  // Note: |speculative_web_ui_| must be initialized before starting the
-  // |speculative_render_frame_host_| creation steps otherwise the WebUI
-  // won't be properly initialized.
-  speculative_web_ui_ = CreateWebUI(url, bindings);
+  CHECK(!current_web_ui_is_navigating_);
 
   // The process for the new SiteInstance may (if we're sharing a process with
   // another host that already initialized it) or may not (we have our own
@@ -1765,19 +1749,13 @@ bool RenderFrameHostManager::CreateSpeculativeRenderFrameHost(
   if (delegate_->IsHidden())
     create_render_frame_flags |= CREATE_RF_HIDDEN;
   speculative_render_frame_host_ =
-      CreateRenderFrame(new_instance, speculative_web_ui_.get(),
-                        create_render_frame_flags, nullptr);
+      CreateRenderFrame(new_instance, create_render_frame_flags, nullptr);
 
-  if (!speculative_render_frame_host_) {
-    speculative_web_ui_.reset();
-    return false;
-  }
-  return true;
+  return !!speculative_render_frame_host_;
 }
 
 scoped_ptr<RenderFrameHostImpl> RenderFrameHostManager::CreateRenderFrame(
     SiteInstance* instance,
-    WebUIImpl* web_ui,
     int flags,
     int* view_routing_id_ptr) {
   bool swapped_out = !!(flags & CREATE_RF_SWAPPED_OUT);
@@ -1895,21 +1873,6 @@ scoped_ptr<RenderFrameHostImpl> RenderFrameHostManager::CreateRenderFrame(
     }
   }
 
-  // When a new RenderView is created by the renderer process, the new
-  // WebContents gets a RenderViewHost in the SiteInstance of its opener
-  // WebContents. If not used in the first navigation, this RVH is swapped out
-  // and is not granted bindings, so we may need to grant them when swapping it
-  // in.
-  if (web_ui && !new_render_frame_host->GetProcess()->IsForGuestsOnly()) {
-    int required_bindings = web_ui->GetBindings();
-    RenderViewHost* render_view_host =
-        new_render_frame_host->render_view_host();
-    if ((render_view_host->GetEnabledBindings() & required_bindings) !=
-            required_bindings) {
-      render_view_host->AllowBindings(required_bindings);
-    }
-  }
-
   // Returns the new RFH if it isn't swapped out.
   if (success && !swapped_out) {
     DCHECK(new_render_frame_host->GetSiteInstance() == instance);
@@ -2028,31 +1991,6 @@ bool RenderFrameHostManager::InitRenderView(
   if (render_view_host->IsRenderViewLive())
     return true;
 
-  // If |render_view_host| is not for a proxy and the navigation is to a WebUI,
-  // and if the RenderView is not in a guest process, tell |render_view_host|
-  // about any bindings it will need enabled.
-  // TODO(carlosk): Move WebUI to RenderFrameHost in https://crbug.com/508850.
-  WebUIImpl* dest_web_ui = nullptr;
-  if (!proxy) {
-    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kEnableBrowserSideNavigation)) {
-      dest_web_ui =
-          should_reuse_web_ui_ ? web_ui_.get() : speculative_web_ui_.get();
-    } else {
-      dest_web_ui = pending_web_ui();
-    }
-  }
-  if (dest_web_ui && !render_view_host->GetProcess()->IsForGuestsOnly()) {
-    render_view_host->AllowBindings(dest_web_ui->GetBindings());
-  } else {
-    // Ensure that we don't create an unprivileged RenderView in a WebUI-enabled
-    // process unless it's swapped out.
-    if (render_view_host->is_active()) {
-      CHECK(!ChildProcessSecurityPolicyImpl::GetInstance()->HasWebUIBindings(
-                render_view_host->GetProcess()->GetID()));
-    }
-  }
-
   int opener_frame_routing_id =
       GetOpenerRoutingID(render_view_host->GetSiteInstance());
 
@@ -2144,42 +2082,17 @@ int RenderFrameHostManager::GetRoutingIdForSiteInstance(
 void RenderFrameHostManager::CommitPending() {
   TRACE_EVENT1("navigation", "RenderFrameHostManager::CommitPending",
                "FrameTreeNode id", frame_tree_node_->frame_tree_node_id());
-  bool browser_side_navigation =
-      base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableBrowserSideNavigation);
-
   // First check whether we're going to want to focus the location bar after
   // this commit.  We do this now because the navigation hasn't formally
-  // committed yet, so if we've already cleared |pending_web_ui_| the call chain
+  // committed yet, so if we've already cleared the pending WebUI the call chain
   // this triggers won't be able to figure out what's going on.
   bool will_focus_location_bar = delegate_->FocusLocationBarByDefault();
 
-  // Next commit the Web UI, if any. Either replace |web_ui_| with
-  // |pending_web_ui_|, or clear |web_ui_| if there is no pending WebUI, or
-  // leave |web_ui_| as is if reusing it.
-  DCHECK(!(pending_web_ui_ && pending_and_current_web_ui_));
-  if (pending_web_ui_ || speculative_web_ui_) {
-    DCHECK(!should_reuse_web_ui_);
-    web_ui_.reset(browser_side_navigation ? speculative_web_ui_.release()
-                                          : pending_web_ui_.release());
-  } else if (pending_and_current_web_ui_ || should_reuse_web_ui_) {
-    if (browser_side_navigation) {
-      DCHECK(web_ui_);
-      should_reuse_web_ui_ = false;
-    } else {
-      DCHECK_EQ(pending_and_current_web_ui_.get(), web_ui_.get());
-      pending_and_current_web_ui_.reset();
-    }
-  } else {
-    web_ui_.reset();
-  }
-  DCHECK(!speculative_web_ui_);
-  DCHECK(!should_reuse_web_ui_);
-
-  // It's possible for the pending_render_frame_host_ to be nullptr when we
-  // aren't crossing process boundaries. If so, we just needed to handle the Web
-  // UI committing above and we're done.
   if (!pending_render_frame_host_ && !speculative_render_frame_host_) {
+    DCHECK_EQ(current_web_ui_is_navigating_, !!render_frame_host_->web_ui());
+    current_web_ui_is_navigating_ = false;
+    // If there's no pending/speculative RenderFrameHost then the current
+    // RenderFrameHost is committing.
     if (will_focus_location_bar)
       delegate_->SetFocusToLocationBar(false);
     return;
@@ -2196,7 +2109,8 @@ void RenderFrameHostManager::CommitPending() {
   // Swap in the pending or speculative frame and make it active. Also ensure
   // the FrameTree stays in sync.
   scoped_ptr<RenderFrameHostImpl> old_render_frame_host;
-  if (!browser_side_navigation) {
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation)) {
     DCHECK(!speculative_render_frame_host_);
     old_render_frame_host =
         SetRenderFrameHost(pending_render_frame_host_.Pass());
@@ -2366,9 +2280,6 @@ RenderFrameHostImpl* RenderFrameHostManager::UpdateStateForNavigate(
       dest_url, source_instance, dest_instance, nullptr, transition,
       dest_is_restore, dest_is_view_source_mode);
 
-  const NavigationEntry* current_entry =
-      delegate_->GetLastCommittedNavigationEntryForRenderManager();
-
   DCHECK(!pending_render_frame_host_);
 
   if (new_instance.get() != current_instance) {
@@ -2381,17 +2292,21 @@ RenderFrameHostImpl* RenderFrameHostManager::UpdateStateForNavigate(
 
     // New SiteInstance: create a pending RFH to navigate.
 
-    // This will possibly create (set to nullptr) a Web UI object for the
-    // pending page. We'll use this later to give the page special access. This
-    // must happen before the new renderer is created below so it will get
-    // bindings. It must also happen after the above conditional call to
-    // CancelPending(), otherwise CancelPending may clear the pending_web_ui_
-    // and the page will not have its bindings set appropriately.
-    SetPendingWebUI(dest_url, bindings);
+    current_web_ui_is_navigating_ = false;
     CreatePendingRenderFrameHost(current_instance, new_instance.get());
+    DCHECK(pending_render_frame_host_);
     if (!pending_render_frame_host_)
       return nullptr;
 
+    pending_render_frame_host_->UpdateWebUI(dest_url, bindings);
+    if (pending_render_frame_host_->web_ui()) {
+      pending_render_frame_host_->web_ui()->RenderViewCreated(
+          pending_render_frame_host_->render_view_host());
+    }
+
+    // We now have a pending RFH and possibly an associated pending WebUI.
+    DCHECK_EQ(GetNavigatingWebUI(), pending_render_frame_host_->web_ui());
+
     // Check if our current RFH is live before we set up a transition.
     if (!render_frame_host_->IsRenderFrameLive()) {
       // The current RFH is not live.  There's no reason to sit around with a
@@ -2404,16 +2319,12 @@ RenderFrameHostImpl* RenderFrameHostManager::UpdateStateForNavigate(
     }
     // Otherwise, it's safe to treat this as a pending cross-process transition.
 
-    // We now have a pending RFH.
-    DCHECK(pending_render_frame_host_);
-
     // We need to wait until the beforeunload handler has run, unless we are
     // transferring an existing request (in which case it has already run).
     // Suspend the new render view (i.e., don't let it send the cross-process
     // Navigate message) until we hear back from the old renderer's
     // beforeunload handler.  If the handler returns false, we'll have to
     // cancel the request.
-    //
     DCHECK(!pending_render_frame_host_->are_navigations_suspended());
     bool is_transfer = transferred_request_id != GlobalRequestID();
     if (is_transfer) {
@@ -2448,23 +2359,7 @@ RenderFrameHostImpl* RenderFrameHostManager::UpdateStateForNavigate(
   // delete the proxy.
   proxy_hosts_->Remove(new_instance.get()->GetId());
 
-  if (ShouldReuseWebUI(current_entry, dest_url)) {
-    pending_web_ui_.reset();
-    pending_and_current_web_ui_ = web_ui_->AsWeakPtr();
-  } else {
-    SetPendingWebUI(dest_url, bindings);
-    // Make sure the new RenderViewHost has the right bindings.
-    if (pending_web_ui() &&
-        !render_frame_host_->GetProcess()->IsForGuestsOnly()) {
-      render_frame_host_->render_view_host()->AllowBindings(
-          pending_web_ui()->GetBindings());
-    }
-  }
-
-  if (pending_web_ui() && render_frame_host_->IsRenderFrameLive()) {
-    pending_web_ui()->RenderViewReused(render_frame_host_->render_view_host(),
-                                       frame_tree_node_->IsMainFrame());
-  }
+  UpdateWebUIOnCurrentFrameHost(dest_url, dest_is_restore, bindings);
 
   // The renderer can exit view source mode when any error or cancellation
   // happen. We must overwrite to recover the mode.
@@ -2477,9 +2372,39 @@ RenderFrameHostImpl* RenderFrameHostManager::UpdateStateForNavigate(
   return render_frame_host_.get();
 }
 
+void RenderFrameHostManager::UpdateWebUIOnCurrentFrameHost(const GURL& dest_url,
+                                                           bool dest_is_restore,
+                                                           int bindings) {
+  WebUI::TypeID previous_web_ui_type = render_frame_host_->web_ui_type();
+  bool changed_web_ui = render_frame_host_->UpdateWebUI(dest_url, bindings);
+
+  // If a change in WebUI happened, check this is an acceptable case.
+  if (changed_web_ui)
+    CheckWebUITransition(previous_web_ui_type, dest_url, dest_is_restore);
+
+  // If there is a WebUI in the current RenderFrameHost, it will navigate.
+  current_web_ui_is_navigating_ = !!render_frame_host_->web_ui();
+  DCHECK_EQ(GetNavigatingWebUI(), render_frame_host_->web_ui());
+
+  // If the current RenderFrameHost has a WebUI and the associated RenderFrame
+  // is alive, notify to the WebUI that the RenderView is being created or
+  // reused depending on whether the WebUI was changed or not.
+  if (GetNavigatingWebUI() && render_frame_host_->IsRenderFrameLive()) {
+    if (changed_web_ui) {
+      GetNavigatingWebUI()->RenderViewCreated(
+          render_frame_host_->render_view_host());
+    } else {
+      GetNavigatingWebUI()->RenderViewReused(
+          render_frame_host_->render_view_host(),
+          frame_tree_node_->IsMainFrame());
+    }
+  }
+}
+
 void RenderFrameHostManager::CancelPending() {
   TRACE_EVENT1("navigation", "RenderFrameHostManager::CancelPending",
                "FrameTreeNode id", frame_tree_node_->frame_tree_node_id());
+  current_web_ui_is_navigating_ = false;
   DiscardUnusedFrame(UnsetPendingRenderFrameHost());
 }
 
@@ -2492,12 +2417,11 @@ RenderFrameHostManager::UnsetPendingRenderFrameHost() {
       pending_render_frame_host.get(),
       render_frame_host_.get());
 
+  current_web_ui_is_navigating_ = false;
+
   // We no longer need to prevent the process from exiting.
   pending_render_frame_host->GetProcess()->RemovePendingView();
 
-  pending_web_ui_.reset();
-  pending_and_current_web_ui_.reset();
-
   return pending_render_frame_host.Pass();
 }
 
@@ -2672,8 +2596,7 @@ void RenderFrameHostManager::CreateOpenerProxiesForFrameTree(
         frame_tree->root()->render_manager()->CreateRenderFrameProxy(instance);
       } else {
         frame_tree->root()->render_manager()->CreateRenderFrame(
-            instance, nullptr, CREATE_RF_SWAPPED_OUT | CREATE_RF_HIDDEN,
-            nullptr);
+            instance, CREATE_RF_SWAPPED_OUT | CREATE_RF_HIDDEN, nullptr);
       }
     }
   }
@@ -2688,4 +2611,51 @@ int RenderFrameHostManager::GetOpenerRoutingID(SiteInstance* instance) {
       ->GetRoutingIdForSiteInstance(instance);
 }
 
+void RenderFrameHostManager::CheckWebUITransition(
+    WebUI::TypeID previous_web_ui_type,
+    const GURL& dest_url,
+    bool dest_is_restore) {
+  // There are a few navigation cases that allow for changes to the WebUI of
+  // the current RenderFrameHost.
+  BrowserContext* browser_context =
+      delegate_->GetControllerForRenderManager().GetBrowserContext();
+  if (render_frame_host_->web_ui()) {
+    // Switching WebUI from one type to another while keeping the
+    // RenderFrameHost is never acceptable.
+    CHECK(previous_web_ui_type == WebUI::kNoWebUI);
+
+    // Going from not having to having a WebUI is acceptable for:
+    // - The first navigation of this frame.
+    const NavigationEntry* current_entry =
+        delegate_->GetLastCommittedNavigationEntryForRenderManager();
+    bool is_first_navigation_for_frame = !current_entry;
+
+    // - A restore navigation to a WebUI URL.
+    const GURL& current_effective_url =
+        current_entry ? SiteInstanceImpl::GetEffectiveURL(
+                            browser_context, current_entry->GetURL())
+                      : render_frame_host_->GetSiteInstance()->GetSiteURL();
+    bool is_webui_restore =
+        dest_is_restore &&
+        WebUIControllerFactoryRegistry::GetInstance()->UseWebUIForURL(
+            browser_context, current_effective_url);
+
+    // - Navigating back from a special renderer URL.
+    bool is_back_from_renderer_url =
+        current_entry && IsRendererDebugURL(current_entry->GetURL());
+
+    // - Navigating in webview tag guest.
+    bool is_webview_tag_guest =
+        render_frame_host_->GetSiteInstance()->GetSiteURL().SchemeIs(
+            kGuestScheme);
+    CHECK(is_first_navigation_for_frame || is_webui_restore ||
+          is_back_from_renderer_url || is_webview_tag_guest);
+  } else {
+    // Going from having to not having a WebUI is acceptable when Navigating to
+    // a special renderer URL.
+    CHECK(IsRendererDebugURL(
+        SiteInstanceImpl::GetEffectiveURL(browser_context, dest_url)));
+  }
+}
+
 }  // namespace content