Revert "[ozone/wayland] Manually handle fullscreen states."

This reverts commit 8f2591ae.

Reason for revert: Likely broke DesktopMediaPickerViewsTest.
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Mac10.10%20Tests/33273

Original change's description:
> [ozone/wayland] Manually handle fullscreen states.
> 
> In order to ensure media files can enter fullscreen mode, manually
> handle fullscreen states. Basically, a compositor sends configuration
> events on each request for state changes from clients asynchronously,
> which is unefficient for media files when they enter a fullscreen mode.
> 
> For example, when a youtube video file is being set to fullscreen, a
> WaylandWindow is also set to a fullscreen mode, but the return value from
> the WaylandWindow::GetPlatformWindowState still contains an old value until
> the compositor calls with a configuration event. This short race is
> enough for a media content to be placed in a forever "entering fullscreen"
> state, which never results in a fullscreen state for media files.
> 
> Bug: 843018
> TEST: XdgVersionV5Test/WaylandWindowTest.SetFullscreenAndRestore/0
> XdgVersionV6Test/WaylandWindowTest.SetFullscreenAndRestore/0
> 
> Change-Id: Ib9bc8c0ce09412c36437d165efc6a0cad60c4d17
> Reviewed-on: https://chromium-review.googlesource.com/1107636
> Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
> Commit-Queue: Maksim Sisov <msisov@igalia.com>
> Cr-Commit-Position: refs/heads/master@{#569172}

TBR=rjkroege@chromium.org,msisov@igalia.com

Change-Id: I9920185d61395a70663fa184e834592f02176da3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 843018
Reviewed-on: https://chromium-review.googlesource.com/1110057Reviewed-by: Martin Šrámek <msramek@chromium.org>
Commit-Queue: Martin Šrámek <msramek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569239}

ui/ozone/platform/wayland/wayland_window.cc

@@ -236,13 +236,6 @@ void WaylandWindow::ToggleFullscreen() {
   // if xdg_surface_set_fullscreen() is not provided with wl_output, it's up to
   // the compositor to choose which display will be used to map this surface.
   if (!IsFullscreen()) {
-    // Fullscreen state changes have to be handled manually and then checked
-    // against configuration events, which come from a compositor. The reason
-    // of manually changing the |state_| is that the compositor answers about
-    // state changes asynchronously, which leads to a wrong return value in
-    // DesktopWindowTreeHostPlatform::IsFullscreen, for example, and media
-    // files can never be set to fullscreen.
-    state_ = PlatformWindowState::PLATFORM_WINDOW_STATE_FULLSCREEN;
     // Client might have requested a fullscreen state while the window was in
     // a maximized state. Thus, |restored_bounds_| can contain the bounds of a
     // "normal" state before the window was maximized. We don't override them
@@ -252,9 +245,6 @@ void WaylandWindow::ToggleFullscreen() {
       restored_bounds_ = bounds_;
     xdg_surface_->SetFullscreen();
   } else {
-    // Check the comment above. If it's not handled synchronously, media files
-    // may not leave the fullscreen mode.
-    state_ = PlatformWindowState::PLATFORM_WINDOW_STATE_UNKNOWN;
     xdg_surface_->UnSetFullscreen();
   }
 
@@ -392,11 +382,6 @@ void WaylandWindow::HandleSurfaceConfigure(int32_t width,
                                            bool is_activated) {
   // Propagate the window state information to the client.
   PlatformWindowState old_state = state_;
-
-  // Ensure that manually handled state changes to fullscreen correspond to the
-  // configuration events from a compositor.
-  DCHECK(is_fullscreen == IsFullscreen());
-
   // There are two cases, which must be handled for the minimized state.
   // The first one is the case, when the surface goes into the minimized state
   // (check comment in WaylandWindow::Minimize), and the second case is when the
@@ -407,10 +392,7 @@ void WaylandWindow::HandleSurfaceConfigure(int32_t width,
     is_minimizing_ = false;
     state_ = PlatformWindowState::PLATFORM_WINDOW_STATE_MINIMIZED;
   } else if (is_fullscreen) {
-    // To ensure the |delegate_| is notified about state changes to fullscreen,
-    // assume the old_state is UNKNOWN (check comment in ToggleFullscreen).
-    old_state = PlatformWindowState::PLATFORM_WINDOW_STATE_UNKNOWN;
-    DCHECK(state_ == PlatformWindowState::PLATFORM_WINDOW_STATE_FULLSCREEN);
+    state_ = PlatformWindowState::PLATFORM_WINDOW_STATE_FULLSCREEN;
   } else if (is_maximized) {
     state_ = PlatformWindowState::PLATFORM_WINDOW_STATE_MAXIMIZED;
   } else {

ui/ozone/platform/wayland/wayland_window_unittest.cc

@@ -173,9 +173,6 @@ TEST_P(WaylandWindowTest, Minimize) {
 }
 
 TEST_P(WaylandWindowTest, SetFullscreenAndRestore) {
-  // Ensure the initial state is unknown.
-  EXPECT_EQ(window_->GetPlatformWindowState(), PLATFORM_WINDOW_STATE_UNKNOWN);
-
   wl_array states;
   InitializeWlArrayWithActivatedState(&states);
 
@@ -185,10 +182,6 @@ TEST_P(WaylandWindowTest, SetFullscreenAndRestore) {
   EXPECT_CALL(delegate_,
               OnWindowStateChanged(Eq(PLATFORM_WINDOW_STATE_FULLSCREEN)));
   window_->ToggleFullscreen();
-  // Make sure than WaylandWindow manually handles fullscreen states. Check the
-  // comment in the WaylandWindow::ToggleFullscreen.
-  EXPECT_EQ(window_->GetPlatformWindowState(),
-            PLATFORM_WINDOW_STATE_FULLSCREEN);
   SendConfigureEvent(0, 0, 1, &states);
   Sync();
 
@@ -196,7 +189,6 @@ TEST_P(WaylandWindowTest, SetFullscreenAndRestore) {
   EXPECT_CALL(delegate_,
               OnWindowStateChanged(Eq(PLATFORM_WINDOW_STATE_NORMAL)));
   window_->Restore();
-  EXPECT_EQ(window_->GetPlatformWindowState(), PLATFORM_WINDOW_STATE_UNKNOWN);
   // Reinitialize wl_array, which removes previous old states.
   InitializeWlArrayWithActivatedState(&states);
   SendConfigureEvent(0, 0, 2, &states);