Fenced Frames: Navigations always replace the current entry

Background:
Fenced frames can navigate themselves but their history is not part of
the browser back/forward list as that could be a communication channel
from the fenced frame to the embedding page. This aligns with MPArch's
disjoint back/forward list for nested frame trees. (For shadowDOM, this
would be achieved with additional API level restrictions like
history.length always returning 1 etc.)

Current Change:
This CL focuses on fenced frames to always have a replacement-only
navigation which was decided due to being a simpler model since it
doesn't imply that there's a hidden list of back/forward entries for
the nested page, only accessible via history APIs and not via the
back/forward buttons. This is also consistent with the iframes new
opt-in mode for disjoint session history as discussed in
whatwg/html#6501.
This change affects both shadowDOM and MPArch versions.

Design:
https://docs.google.com/document/d/17rtX55WkxMcfh6ipuhP4mNULIVxUApvYt4ZYXfX2x-s/edit#heading=h.af2cik2j1rbs

This CL includes browser tests to check the NavigationController's entry
count and
https://chromium-review.googlesource.com/c/chromium/src/+/3227344
added WPTs for all the history API surface.

Bug: 1242533
Change-Id: Ic574ee1bf87ce3a53dde7d280abaa46233d85b0d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3216452
Reviewed-by: Reilly Grant <[email protected]>
Reviewed-by: Dave Tapuska <[email protected]>
Reviewed-by: Rakina Zata Amni <[email protected]>
Reviewed-by: Jeremy Roman <[email protected]>
Reviewed-by: Lei Zhang <[email protected]>
Reviewed-by: Alex Moshchuk <[email protected]>
Commit-Queue: Dave Tapuska <[email protected]>
Commit-Queue: Shivani Sharma <[email protected]>
Cr-Commit-Position: refs/heads/main@{#938761}
NOKEYCHECK=True
GitOrigin-RevId: 5e37873045b5e4c8cd4244480476a2b0c23b8114

blink/public/web/web_view.h

@@ -101,6 +101,7 @@ class WebView {
   // |is_prerendering| defines whether the page is being prerendered by the
   // Prerender2 feature (see content/browser/prerender/README.md).
   // [is_inside_portal] defines whether the page is inside_portal.
+  // [is_fenced_frame] defines whether the page is for a fenced frame.
   // |compositing_enabled| dictates whether accelerated compositing should be
   // enabled for the page. It must be false if no clients are provided, or if a
   // LayerTreeView will not be set for the WebWidget.
@@ -125,6 +126,7 @@ class WebView {
       bool is_hidden,
       bool is_prerendering,
       bool is_inside_portal,
+      bool is_fenced_frame,
       bool compositing_enabled,
       bool widgets_never_composited,
       WebView* opener,

blink/renderer/core/exported/web_view_impl.cc

@@ -448,6 +448,7 @@ WebView* WebView::Create(
     bool is_hidden,
     bool is_prerendering,
     bool is_inside_portal,
+    bool is_fenced_frame,
     bool compositing_enabled,
     bool widgets_never_composited,
     WebView* opener,
@@ -460,7 +461,7 @@ WebView* WebView::Create(
       client,
       is_hidden ? mojom::blink::PageVisibilityState::kHidden
                 : mojom::blink::PageVisibilityState::kVisible,
-      is_prerendering, is_inside_portal, compositing_enabled,
+      is_prerendering, is_inside_portal, is_fenced_frame, compositing_enabled,
       widgets_never_composited, To<WebViewImpl>(opener), std::move(page_handle),
       agent_group_scheduler, session_storage_namespace_id,
       std::move(page_base_background_color));
@@ -471,6 +472,7 @@ WebViewImpl* WebViewImpl::Create(
     mojom::blink::PageVisibilityState visibility,
     bool is_prerendering,
     bool is_inside_portal,
+    bool is_fenced_frame,
     bool compositing_enabled,
     bool widgets_never_composited,
     WebViewImpl* opener,
@@ -481,7 +483,7 @@ WebViewImpl* WebViewImpl::Create(
   // Take a self-reference for WebViewImpl that is released by calling Close(),
   // then return a raw pointer to the caller.
   auto web_view = base::AdoptRef(new WebViewImpl(
-      client, visibility, is_prerendering, is_inside_portal,
+      client, visibility, is_prerendering, is_inside_portal, is_fenced_frame,
       compositing_enabled, widgets_never_composited, opener,
       std::move(page_handle), agent_group_scheduler,
       session_storage_namespace_id, std::move(page_base_background_color)));
@@ -544,6 +546,7 @@ WebViewImpl::WebViewImpl(
     mojom::blink::PageVisibilityState visibility,
     bool is_prerendering,
     bool is_inside_portal,
+    bool is_fenced_frame,
     bool does_composite,
     bool widgets_never_composited,
     WebViewImpl* opener,
@@ -579,6 +582,11 @@ WebViewImpl::WebViewImpl(
   // page.
   SetInsidePortal(is_inside_portal);
 
+  if (is_fenced_frame && features::IsFencedFramesEnabled() &&
+      features::IsFencedFramesMPArchBased()) {
+    page_->SetIsMainFrameFencedFrameRoot();
+  }
+
   // When not compositing, keep the Page in the loop so that it will paint all
   // content into the root layer, as multiple layers can only be used when
   // compositing them together later.

blink/renderer/core/exported/web_view_impl.h

@@ -117,6 +117,7 @@ class CORE_EXPORT WebViewImpl final : public WebView,
       mojom::blink::PageVisibilityState visibility,
       bool is_prerendering,
       bool is_inside_portal,
+      bool is_fenced_frame,
       bool compositing_enabled,
       bool widgets_never_composited,
       WebViewImpl* opener,
@@ -649,6 +650,7 @@ class CORE_EXPORT WebViewImpl final : public WebView,
       mojom::blink::PageVisibilityState visibility,
       bool is_prerendering,
       bool is_inside_portal,
+      bool is_fenced_frame,
       bool does_composite,
       bool widgets_never_composite,
       WebViewImpl* opener,

blink/renderer/core/exported/web_view_test.cc

@@ -489,6 +489,7 @@ TEST_F(WebViewTest, SetBaseBackgroundColorBeforeMainFrame) {
                       /*is_hidden=*/false,
                       /*is_prerendering=*/false,
                       /*is_inside_portal=*/false,
+                      /*is_fenced_frame=*/false,
                       /*compositing_enabled=*/true,
                       /*widgets_never_composited=*/false,
                       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),
@@ -2743,6 +2744,7 @@ TEST_F(WebViewTest, ClientTapHandlingNullWebViewClient) {
   WebViewImpl* web_view = To<WebViewImpl>(WebView::Create(
       /*client=*/nullptr, /*is_hidden=*/false, /*is_prerendering=*/false,
       /*is_inside_portal=*/false,
+      /*is_fenced_frame=*/false,
       /*compositing_enabled=*/false,
       /*widgets_never_composited=*/false,
       /*opener=*/nullptr, mojo::NullAssociatedReceiver(),

blink/renderer/core/frame/frame_test_helpers.cc

@@ -621,6 +621,7 @@ void WebViewHelper::InitializeWebView(TestWebViewClient* web_view_client,
                       /*is_hidden=*/false,
                       /*is_prerendering=*/false,
                       /*is_inside_portal=*/false,
+                      /*is_fenced_frame=*/false,
                       /*compositing_enabled=*/true,
                       /*widgets_never_composited=*/false,
                       /*opener=*/opener, mojo::NullAssociatedReceiver(),

blink/renderer/core/frame/local_frame.cc

@@ -512,12 +512,27 @@ bool LocalFrame::NavigationShouldReplaceCurrentHistoryEntry(
 }
 
 bool LocalFrame::ShouldMaintainTrivialSessionHistory() const {
-  // TODO(https://crbug.com/1197384): We may have to add fenced frames. This
-  // should be kept in sync with NavigationControllerImpl version,
+  // This should be kept in sync with
   // NavigationControllerImpl::ShouldMaintainTrivialSessionHistory.
   //
   // TODO(mcnee): Similarly, we need to restrict orphaned contexts.
-  return GetPage()->InsidePortal() || GetDocument()->IsPrerendering();
+  return GetPage()->InsidePortal() || GetDocument()->IsPrerendering() ||
+         IsInFencedFrameTree();
+}
+
+bool LocalFrame::IsInFencedFrameTree() const {
+  if (!blink::features::IsFencedFramesEnabled())
+    return false;
+
+  switch (blink::features::kFencedFramesImplementationTypeParam.Get()) {
+    case blink::features::FencedFramesImplementationType::kMPArch:
+      return GetPage()->IsMainFrameFencedFrameRoot();
+    case blink::features::FencedFramesImplementationType::kShadowDOM:
+      return Tree().Top(FrameTreeBoundary::kFenced) !=
+             Tree().Top(FrameTreeBoundary::kIgnoreFence);
+    default:
+      return false;
+  }
 }
 
 bool LocalFrame::DetachImpl(FrameDetachType type) {

blink/renderer/core/frame/local_frame.h

@@ -804,6 +804,13 @@ class CORE_EXPORT LocalFrame final : public Frame,
       const FrameLoadRequest& request,
       WebFrameLoadType frame_load_type);
 
+  // Returns false if fenced frames are disabled. Returns true if the
+  // feature is enabled and if |this| or any of its ancestor nodes is a
+  // fenced frame. For MPArch returns the value of
+  // Page::IsMainFrameFencedFrameRoot and for shadowDOM returns true, if
+  // the FrameTree that this frame is in is not the outermost FrameTree.
+  bool IsInFencedFrameTree() const;
+
   std::unique_ptr<FrameScheduler> frame_scheduler_;
 
   // Holds all PauseSubresourceLoadingHandles allowing either |this| to delete

blink/renderer/core/page/page.cc

@@ -1079,6 +1079,14 @@ bool Page::InsidePortal() const {
   return inside_portal_;
 }
 
+void Page::SetIsMainFrameFencedFrameRoot() {
+  is_fenced_frame_tree_ = true;
+}
+
+bool Page::IsMainFrameFencedFrameRoot() const {
+  return is_fenced_frame_tree_;
+}
+
 void Page::SetMediaFeatureOverride(const AtomicString& media_feature,
                                    const String& value) {
   if (!media_feature_overrides_) {

blink/renderer/core/page/page.h

@@ -385,6 +385,11 @@ class CORE_EXPORT Page final : public GarbageCollected<Page>,
   // Fully invalidate paint of all local frames in this page.
   void InvalidatePaint();
 
+  // Should be invoked when the main frame of this frame tree is a fenced frame.
+  void SetIsMainFrameFencedFrameRoot();
+  // Returns if the main frame of this frame tree is a fenced frame.
+  bool IsMainFrameFencedFrameRoot() const;
+
  private:
   friend class ScopedPagePauser;
 
@@ -506,6 +511,11 @@ class CORE_EXPORT Page final : public GarbageCollected<Page>,
   // prerender activation; it does not go from false to true.
   bool is_prerendering_ = false;
 
+  // Whether the the Page's main document is a Fenced Frame document. This is
+  // only set for the MPArch implementation and is true when the corresponding
+  // browser side FrameTree has the FrameTree::Type of kFencedFrame.
+  bool is_fenced_frame_tree_ = false;
+
   mojom::blink::TextAutosizerPageInfo web_text_autosizer_page_info_;
 
   WebScopedVirtualTimePauser history_navigation_virtual_time_pauser_;

blink/renderer/modules/peerconnection/webrtc_audio_renderer_test.cc

@@ -144,6 +144,7 @@ class MAYBE_WebRtcAudioRendererTest : public testing::Test {
             /*is_hidden=*/false,
             /*is_prerendering=*/false,
             /*is_inside_portal=*/false,
+            /*is_fenced_frame=*/false,
             /*compositing_enabled=*/false,
             /*widgets_never_composited=*/false,
             /*opener=*/nullptr,