[fuchsia] remove Scenic and GFX dependencies in DesktopCapturer

We previously used:
- fuchsia.ui.scenic.Scenic/UsesFlatland to determine whether to use
  Flatland; from now on it should always be the case, so this check is
  no longer necessary.
- fuchsia.ui.scenic.Scenic/GetDisplayInfo to get
  fuchsia.ui.gfx.DisplayInfo. This has been migrated to
  fuchsia.ui.display.singleton.Info/GetMetrics and
  fuchsia.ui.display.singleton.Metrics.

Bug: fuchsia:100303
Change-Id: I147da9ffdf0ca49e1c5bde5d188e434fc660becc
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/311860
Reviewed-by: Emircan Uysaler <emircan@google.com>
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Caroline Liu <carolineliu@google.com>
Cr-Commit-Position: refs/heads/main@{#40432}

modules/desktop_capture/BUILD.gn

@@ -451,8 +451,7 @@ rtc_library("desktop_capture") {
       "../../rtc_base:divide_round",
       "//third_party/fuchsia-sdk/sdk/fidl/fuchsia.sysmem",
       "//third_party/fuchsia-sdk/sdk/fidl/fuchsia.ui.composition",
-      "//third_party/fuchsia-sdk/sdk/fidl/fuchsia.ui.scenic",
-      "//third_party/fuchsia-sdk/sdk/pkg/scenic_cpp",
+      "//third_party/fuchsia-sdk/sdk/fidl/fuchsia.ui.display.singleton",
       "//third_party/fuchsia-sdk/sdk/pkg/sys_cpp",
     ]
   }

modules/desktop_capture/screen_capturer_fuchsia.cc

@@ -12,7 +12,7 @@
 
 #include <fuchsia/sysmem/cpp/fidl.h>
 #include <fuchsia/ui/composition/cpp/fidl.h>
-#include <fuchsia/ui/scenic/cpp/fidl.h>
+#include <fuchsia/ui/display/singleton/cpp/fidl.h>
 #include <lib/sys/cpp/component_context.h>
 
 #include <algorithm>
@@ -56,17 +56,7 @@ size_t RoundUpToMultiple(size_t value, size_t multiple) {
 
 std::unique_ptr<DesktopCapturer> DesktopCapturer::CreateRawScreenCapturer(
     const DesktopCaptureOptions& options) {
-  if (ScreenCapturerFuchsia::CheckRequirements()) {
-    std::unique_ptr<ScreenCapturerFuchsia> capturer(
-        new ScreenCapturerFuchsia());
-    return capturer;
-  }
-  return nullptr;
-}
-
-ScreenCapturerFuchsia::ScreenCapturerFuchsia()
-    : component_context_(sys::ComponentContext::Create()) {
-  RTC_DCHECK(CheckRequirements());
+  return capturer(new ScreenCapturerFuchsia());
 }
 
 ScreenCapturerFuchsia::~ScreenCapturerFuchsia() {
@@ -82,26 +72,6 @@ ScreenCapturerFuchsia::~ScreenCapturerFuchsia() {
   }
 }
 
-// TODO(fxbug.dev/100303): Remove this function when Flatland is the only API.
-bool ScreenCapturerFuchsia::CheckRequirements() {
-  std::unique_ptr<sys::ComponentContext> component_context =
-      sys::ComponentContext::Create();
-  fuchsia::ui::scenic::ScenicSyncPtr scenic;
-  zx_status_t status = component_context->svc()->Connect(scenic.NewRequest());
-  if (status != ZX_OK) {
-    RTC_LOG(LS_ERROR) << "Failed to connect to Scenic: " << status;
-    return false;
-  }
-
-  bool scenic_uses_flatland = false;
-  scenic->UsesFlatland(&scenic_uses_flatland);
-  if (!scenic_uses_flatland) {
-    RTC_LOG(LS_ERROR) << "Screen capture not supported without Flatland.";
-  }
-
-  return scenic_uses_flatland;
-}
-
 void ScreenCapturerFuchsia::Start(Callback* callback) {
   RTC_DCHECK(!callback_);
   RTC_DCHECK(callback);
@@ -226,24 +196,26 @@ ScreenCapturerFuchsia::GetBufferConstraints() {
 }
 
 void ScreenCapturerFuchsia::SetupBuffers() {
-  fuchsia::ui::scenic::ScenicSyncPtr scenic;
-  zx_status_t status = component_context_->svc()->Connect(scenic.NewRequest());
+  fuchsia::ui::display::singleton::InfoSyncPtr display_info;
+  zx_status_t status =
+      component_context_->svc()->Connect(display_info.NewRequest());
   if (status != ZX_OK) {
     fatal_error_ = true;
-    RTC_LOG(LS_ERROR) << "Failed to connect to Scenic: " << status;
+    RTC_LOG(LS_ERROR)
+        << "Failed to connect to fuchsia.ui.display.singleton.Info: " << status;
     return;
   }
 
-  fuchsia::ui::gfx::DisplayInfo display_info;
-  status = scenic->GetDisplayInfo(&display_info);
+  fuchsia::ui::display::singleton::Metrics metrics;
+  status = display_info->GetMetrics(&metrics);
   if (status != ZX_OK) {
     fatal_error_ = true;
     RTC_LOG(LS_ERROR) << "Failed to connect to get display dimensions: "
                       << status;
     return;
   }
-  width_ = display_info.width_in_px;
-  height_ = display_info.height_in_px;
+  width_ = metrics.extent_in_px().width;
+  height_ = metrics.extent_in_px().height;
 
   status = component_context_->svc()->Connect(sysmem_allocator_.NewRequest());
   if (status != ZX_OK) {

modules/desktop_capture/screen_capturer_fuchsia.h

@@ -29,8 +29,6 @@ class ScreenCapturerFuchsia final : public DesktopCapturer {
   ScreenCapturerFuchsia();
   ~ScreenCapturerFuchsia() override;
 
-  static bool CheckRequirements();
-
   // DesktopCapturer interface.
   void Start(Callback* callback) override;
   void CaptureFrame() override;