Revert "Fix evicted app windows showing as empty in overview"

This reverts commit e9ddea61.

Reason for revert: AppWindowBrowserTest.ShouldShowStaleContentOnEviction is flaky.
https://analysis.chromium.org/p/chromium/flake-portal/flakes/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyVwsSBUZsYWtlIkxjaHJvbWl1bUBicm93c2VyX3Rlc3RzQEFwcFdpbmRvd0Jyb3dzZXJUZXN0LlNob3VsZFNob3dTdGFsZUNvbnRlbnRPbkV2aWN0aW9uDA

Original change's description:
> Fix evicted app windows showing as empty in overview
> 
> The Files app, as well as other apps, if they're evicted due to
> being occluded by other windows, will show as empty for a second or
> more in overview until reloaded.
> 
> This CL makes them behave the same way as browser windows, that is
> they show stale contents until reloaded.
> 
> BUG=986085, 866622
> TEST=Manually, follow steps on bug, and note the issue no longer shows.
> 
> Change-Id: If9a2b26b914fe55672d15d4b560cbe6d7e996591
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1711843
> Reviewed-by: kylechar <kylechar@chromium.org>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Ken Buchanan <kenrb@chromium.org>
> Reviewed-by: Ken Rockot <rockot@google.com>
> Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
> Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#682390}

TBR=sky@chromium.org,kenrb@chromium.org,lazyboy@chromium.org,rockot@google.com,afakhry@chromium.org,kylechar@chromium.org

Change-Id: I7772e1ab6134a02d2cd6ad1d312623b424339693
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 986085, 866622
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1729511Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682759}

content/browser/renderer_host/delegated_frame_host.cc

@@ -81,21 +81,13 @@ DelegatedFrameHost::~DelegatedFrameHost() {
   host_frame_sink_manager_->InvalidateFrameSinkId(frame_sink_id_);
 }
 
-void DelegatedFrameHost::AddObserverForTesting(Observer* observer) {
-  observers_.AddObserver(observer);
-}
-
-void DelegatedFrameHost::RemoveObserverForTesting(Observer* observer) {
-  observers_.RemoveObserver(observer);
-}
-
 void DelegatedFrameHost::WasShown(
     const viz::LocalSurfaceId& new_local_surface_id,
     const gfx::Size& new_dip_size,
     const base::Optional<RecordTabSwitchTimeRequest>&
         record_tab_switch_time_request) {
   // Cancel any pending frame eviction and unpause it if paused.
-  SetFrameEvictionStateAndNotifyObservers(FrameEvictionState::kNotStarted);
+  frame_eviction_state_ = FrameEvictionState::kNotStarted;
 
   frame_evictor_->SetVisible(true);
   if (record_tab_switch_time_request && compositor_) {
@@ -189,16 +181,6 @@ void DelegatedFrameHost::CopyFromCompositingSurfaceInternal(
       viz::SurfaceId(frame_sink_id_, local_surface_id_), std::move(request));
 }
 
-void DelegatedFrameHost::SetFrameEvictionStateAndNotifyObservers(
-    FrameEvictionState frame_eviction_state) {
-  if (frame_eviction_state_ == frame_eviction_state)
-    return;
-
-  frame_eviction_state_ = frame_eviction_state;
-  for (auto& obs : observers_)
-    obs.OnFrameEvictionStateChanged(frame_eviction_state_);
-}
-
 bool DelegatedFrameHost::CanCopyFromCompositingSurface() const {
   return local_surface_id_.is_valid();
 }
@@ -391,8 +373,7 @@ void DelegatedFrameHost::EvictDelegatedFrame() {
   // CrOS overview mode.
   if (client_->ShouldShowStaleContentOnEviction() &&
       !stale_content_layer_->has_external_content()) {
-    SetFrameEvictionStateAndNotifyObservers(
-        FrameEvictionState::kPendingEvictionRequests);
+    frame_eviction_state_ = FrameEvictionState::kPendingEvictionRequests;
     auto callback =
         base::BindOnce(&DelegatedFrameHost::DidCopyStaleContent, GetWeakPtr());
 
@@ -418,7 +399,7 @@ void DelegatedFrameHost::DidCopyStaleContent(
   DCHECK_EQ(result->format(), viz::CopyOutputResult::Format::RGBA_TEXTURE);
 
   DCHECK_NE(frame_eviction_state_, FrameEvictionState::kNotStarted);
-  SetFrameEvictionStateAndNotifyObservers(FrameEvictionState::kNotStarted);
+  frame_eviction_state_ = FrameEvictionState::kNotStarted;
   ContinueDelegatedFrameEviction();
 
   auto transfer_resource = viz::TransferableResource::MakeGL(

content/browser/renderer_host/delegated_frame_host.h

@@ -69,19 +69,6 @@ class CONTENT_EXPORT DelegatedFrameHost
       public viz::mojom::CompositorFrameSinkClient,
       public viz::HostFrameSinkClient {
  public:
-  enum class FrameEvictionState {
-    kNotStarted = 0,          // Frame eviction is ready.
-    kPendingEvictionRequests  // Frame eviction is paused with pending requests.
-  };
-
-  class Observer {
-   public:
-    virtual void OnFrameEvictionStateChanged(FrameEvictionState new_state) = 0;
-
-   protected:
-    virtual ~Observer() = default;
-  };
-
   // |should_register_frame_sink_id| flag indicates whether DelegatedFrameHost
   // is responsible for registering the associated FrameSinkId with the
   // compositor or not. This is set only on non-aura platforms, since aura is
@@ -91,9 +78,6 @@ class CONTENT_EXPORT DelegatedFrameHost
                      bool should_register_frame_sink_id);
   ~DelegatedFrameHost() override;
 
-  void AddObserverForTesting(Observer* observer);
-  void RemoveObserverForTesting(Observer* observer);
-
   // ui::CompositorObserver implementation.
   void OnCompositingShuttingDown(ui::Compositor* compositor) override;
 
@@ -189,14 +173,6 @@ class CONTENT_EXPORT DelegatedFrameHost
     return weak_factory_.GetWeakPtr();
   }
 
-  const ui::Layer* stale_content_layer() const {
-    return stale_content_layer_.get();
-  }
-
-  FrameEvictionState frame_eviction_state() const {
-    return frame_eviction_state_;
-  }
-
  private:
   friend class DelegatedFrameHostClient;
   FRIEND_TEST_ALL_PREFIXES(RenderWidgetHostViewAuraBrowserTest,
@@ -224,9 +200,6 @@ class CONTENT_EXPORT DelegatedFrameHost
       viz::CopyOutputRequest::ResultFormat format,
       viz::CopyOutputRequest::CopyOutputRequestCallback callback);
 
-  void SetFrameEvictionStateAndNotifyObservers(
-      FrameEvictionState frame_eviction_state);
-
   const viz::FrameSinkId frame_sink_id_;
   DelegatedFrameHostClient* const client_;
   const bool enable_viz_;
@@ -258,6 +231,11 @@ class CONTENT_EXPORT DelegatedFrameHost
 
   viz::LocalSurfaceId first_local_surface_id_after_navigation_;
 
+  enum class FrameEvictionState {
+    kNotStarted = 0,          // Frame eviction is ready.
+    kPendingEvictionRequests  // Frame eviction is paused with pending requests.
+  };
+
   FrameEvictionState frame_eviction_state_ = FrameEvictionState::kNotStarted;
 
   // Layer responsible for displaying the stale content for the DFHC when the
@@ -267,8 +245,6 @@ class CONTENT_EXPORT DelegatedFrameHost
 
   TabSwitchTimeRecorder tab_switch_time_recorder_;
 
-  base::ObserverList<Observer>::Unchecked observers_;
-
   base::WeakPtrFactory<DelegatedFrameHost> weak_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(DelegatedFrameHost);

content/browser/renderer_host/render_widget_host_view_aura.h

@@ -459,8 +459,6 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
 
   class WindowAncestorObserver;
   friend class WindowAncestorObserver;
-  friend void VerifyStaleContentOnFrameEviction(
-      RenderWidgetHostView* render_widget_host_view);
 
   // Allocate a new FrameSinkId if this object is the platform view of a
   // RenderWidgetHostViewGuest. This FrameSinkId will not be actually used in

content/public/test/browser_test_utils.cc

@@ -137,7 +137,6 @@
 #endif
 
 #if defined(USE_AURA)
-#include "content/browser/renderer_host/delegated_frame_host.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 #include "ui/aura/test/window_event_dispatcher_test_api.h"
@@ -3093,78 +3092,6 @@ MockOverscrollController* MockOverscrollController::Create(
   return raw_mock;
 }
 
-namespace {
-
-// This class interacts with the internals of the DelegatedFrameHost without
-// exposing them in the header.
-class EvictionStateWaiter : public DelegatedFrameHost::Observer {
- public:
-  EvictionStateWaiter(DelegatedFrameHost* delegated_frame_host)
-      : delegated_frame_host_(delegated_frame_host) {
-    delegated_frame_host_->AddObserverForTesting(this);
-  }
-
-  ~EvictionStateWaiter() override {
-    delegated_frame_host_->RemoveObserverForTesting(this);
-  }
-
-  void WaitForEvictionState(DelegatedFrameHost::FrameEvictionState state) {
-    if (delegated_frame_host_->frame_eviction_state() == state)
-      return;
-
-    waited_eviction_state_ = state;
-    base::RunLoop run_loop;
-    quit_closure_ = run_loop.QuitClosure();
-    run_loop.Run();
-  }
-
-  // DelegatedFrameHost::Observer:
-  void OnFrameEvictionStateChanged(
-      DelegatedFrameHost::FrameEvictionState new_state) override {
-    if (!quit_closure_.is_null() && (new_state == waited_eviction_state_))
-      std::move(quit_closure_).Run();
-  }
-
- private:
-  DelegatedFrameHost* delegated_frame_host_;
-  DelegatedFrameHost::FrameEvictionState waited_eviction_state_;
-  base::OnceClosure quit_closure_;
-
-  DISALLOW_COPY_AND_ASSIGN(EvictionStateWaiter);
-};
-
-}  // namespace
-
-void VerifyStaleContentOnFrameEviction(
-    RenderWidgetHostView* render_widget_host_view) {
-  auto* render_widget_host_view_aura =
-      static_cast<RenderWidgetHostViewAura*>(render_widget_host_view);
-  DelegatedFrameHost* delegated_frame_host =
-      render_widget_host_view_aura->GetDelegatedFrameHost();
-
-  // Initially there should be no stale content set.
-  EXPECT_FALSE(
-      delegated_frame_host->stale_content_layer()->has_external_content());
-  EXPECT_EQ(delegated_frame_host->frame_eviction_state(),
-            DelegatedFrameHost::FrameEvictionState::kNotStarted);
-
-  // Hide the view and evict the frame, and expect that stale content will be
-  // set.
-  EvictionStateWaiter waiter{delegated_frame_host};
-  render_widget_host_view_aura->WasOccluded();
-  static_cast<viz::FrameEvictorClient*>(delegated_frame_host)
-      ->EvictDelegatedFrame();
-  EXPECT_EQ(delegated_frame_host->frame_eviction_state(),
-            DelegatedFrameHost::FrameEvictionState::kPendingEvictionRequests);
-  // Wait until the stale frame content is copied and set onto the layer, i.e.
-  // the eviction state changes from kPendingEvictionRequests back to
-  // kNotStarted.
-  waiter.WaitForEvictionState(
-      DelegatedFrameHost::FrameEvictionState::kNotStarted);
-  EXPECT_TRUE(
-      delegated_frame_host->stale_content_layer()->has_external_content());
-}
-
 #endif  // defined(USE_AURA)
 
 ContextMenuFilter::ContextMenuFilter()

content/public/test/browser_test_utils.h

@@ -1590,12 +1590,6 @@ class MockOverscrollController {
   // Waits until the mock receives a consumed GestureScrollUpdate.
   virtual void WaitForConsumedScroll() = 0;
 };
-
-// Tests that a |render_widget_host_view| stores a stale content when its frame
-// gets evicted. |render_widget_host_view| has to be a RenderWidgetHostViewAura.
-void VerifyStaleContentOnFrameEviction(
-    RenderWidgetHostView* render_widget_host_view);
-
 #endif  // defined(USE_AURA)
 
 // This class filters for FrameHostMsg_ContextMenu messages coming in

extensions/browser/app_window/app_window.cc

@@ -454,10 +454,6 @@ void AppWindow::ExitPictureInPicture() {
   app_delegate_->ExitPictureInPicture();
 }
 
-bool AppWindow::ShouldShowStaleContentOnEviction(content::WebContents* source) {
-  return true;
-}
-
 bool AppWindow::OnMessageReceived(const IPC::Message& message,
                                   content::RenderFrameHost* render_frame_host) {
   bool handled = true;

extensions/browser/app_window/app_window.h

@@ -451,7 +451,6 @@ class AppWindow : public content::WebContentsDelegate,
       const viz::SurfaceId& surface_id,
       const gfx::Size& natural_size) override;
   void ExitPictureInPicture() override;
-  bool ShouldShowStaleContentOnEviction(content::WebContents* source) override;
 
   // content::WebContentsObserver implementation.
   bool OnMessageReceived(const IPC::Message& message,

extensions/browser/app_window/app_window_browsertest.cc

@@ -66,18 +66,6 @@ IN_PROC_BROWSER_TEST_F(AppWindowBrowserTest, FrameInsetsForNoFrame) {
   CloseAppWindow(app_window);
 }
 
-#if defined(OS_CHROMEOS)
-
-IN_PROC_BROWSER_TEST_F(AppWindowBrowserTest, ShouldShowStaleContentOnEviction) {
-  AppWindow* app_window = CreateTestAppWindow("{}");
-  // Helper function as this test requires inspecting a number of content::
-  // internal objects.
-  content::VerifyStaleContentOnFrameEviction(
-      app_window->web_contents()->GetRenderWidgetHostView());
-}
-
-#endif  // defined(OS_CHROMEOS)
-
 }  // namespace
 
 }  // namespace extensions