Stop-gap workaround for the graphics issue in CTS+nocturne

Bug: b/148977363
Change-Id: I3568916986b9b5b8917e1ca3afa2cb0be126d150
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2104653Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#750588}

components/exo/wayland/zcr_remote_shell.cc

@@ -197,6 +197,20 @@ uint32_t CaptionButtonMask(uint32_t mask) {
   return caption_button_icon_mask;
 }
 
+void MaybeApplyCTSHack(int layout_mode,
+                       const gfx::Size& size_in_pixel,
+                       gfx::Insets* insets_in_client_pixel,
+                       gfx::Insets* stable_insets_in_client_pixel) {
+  constexpr int kBadBottomInsets = 90;
+  if (layout_mode == ZCR_REMOTE_SHELL_V1_LAYOUT_MODE_TABLET &&
+      size_in_pixel.width() == 3000 && size_in_pixel.height() == 2000 &&
+      stable_insets_in_client_pixel->bottom() == kBadBottomInsets) {
+    stable_insets_in_client_pixel->set_bottom(kBadBottomInsets + 1);
+    if (insets_in_client_pixel->bottom() == kBadBottomInsets)
+      insets_in_client_pixel->set_bottom(kBadBottomInsets + 1);
+  }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // remote_surface_interface:
 
@@ -890,6 +904,10 @@ class WaylandRemoteShell : public ash::TabletModeObserver,
                                            size_in_client_pixel,
                                            GetStableWorkArea(display));
 
+        // TODO(b/148977363): Fix the issue and remove the hack.
+        MaybeApplyCTSHack(layout_mode_, size_in_pixel, &insets_in_client_pixel,
+                          &stable_insets_in_client_pixel);
+
         int systemui_visibility =
             shelf_layout_manager->visibility_state() == ash::SHELF_AUTO_HIDE
                 ? ZCR_REMOTE_SURFACE_V1_SYSTEMUI_VISIBILITY_STATE_AUTOHIDE_NON_STICKY