[cros] Treat windows as visible while they are being captured.

On CrOS, a window can be occluded by another window, causing content running
in full-occluded windows not be rendered.  Windows that are being
captured (e.g. for screen-sharing) should continue to render even
when fully-occluded.

Bug: 935971
Test: covered by unittests
Change-Id: Ib3098f2a85aa0bb3924924732d22b7c51d125c60
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1540101Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#646671}

content/browser/media/capture/aura_window_video_capture_device.cc

@@ -11,6 +11,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/browser/media/capture/mouse_cursor_overlay_controller.h"
@@ -21,6 +22,7 @@
 #include "mojo/public/cpp/bindings/strong_binding.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
+#include "ui/aura/window_occlusion_tracker.h"
 
 #if defined(OS_CHROMEOS)
 #include "content/browser/media/capture/lame_window_capturer_chromeos.h"
@@ -86,6 +88,9 @@ class AuraWindowVideoCaptureDevice::WindowTracker
         target_window_->GetFrameSinkId().is_valid() &&
 #endif
         true) {
+#if defined(OS_CHROMEOS)
+      force_visible_.emplace(target_window_);
+#endif
       target_window_->AddObserver(this);
       device_task_runner_->PostTask(
           FROM_HERE,
@@ -111,6 +116,9 @@ class AuraWindowVideoCaptureDevice::WindowTracker
 
     target_window_->RemoveObserver(this);
     target_window_ = nullptr;
+#if defined(OS_CHROMEOS)
+    force_visible_.reset();
+#endif
 
     device_task_runner_->PostTask(
         FROM_HERE,
@@ -132,6 +140,10 @@ class AuraWindowVideoCaptureDevice::WindowTracker
   const DesktopMediaID::Type target_type_;
 
   aura::Window* target_window_ = nullptr;
+#if defined(OS_CHROMEOS)
+  base::Optional<aura::WindowOcclusionTracker::ScopedForceVisible>
+      force_visible_;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(WindowTracker);
 };

content/browser/media/capture/aura_window_video_capture_device_browsertest.cc

@@ -311,6 +311,34 @@ IN_PROC_BROWSER_TEST_F(AuraWindowVideoCaptureDeviceBrowserTest,
   StopAndDeAllocate();
 }
 
+#if defined(OS_CHROMEOS)
+// On ChromeOS, another window may occlude a window that is being captured.
+// Make sure the visibility is set to visible during capture if it's occluded.
+IN_PROC_BROWSER_TEST_F(AuraWindowVideoCaptureDeviceBrowserTest,
+                       CapturesOccludedWindows) {
+  // TODO(crbug.com/877172): CopyOutputRequests not allowed.
+  if (features::IsSingleProcessMash())
+    return;
+  NavigateToInitialDocument();
+  AllocateAndStartAndWaitForFirstFrame();
+
+  ASSERT_EQ(aura::Window::OcclusionState::VISIBLE,
+            shell()->web_contents()->GetNativeView()->occlusion_state());
+  // Create a window on top of the window being captured with same size so that
+  // it is occluded.
+  auto window = std::make_unique<aura::Window>(nullptr);
+  window->Init(ui::LAYER_TEXTURED);
+  shell()->window()->GetRootWindow()->AddChild(window.get());
+  window->SetBounds(shell()->window()->bounds());
+  window->Show();
+  EXPECT_EQ(aura::Window::OcclusionState::VISIBLE,
+            shell()->web_contents()->GetNativeView()->occlusion_state());
+
+  window.reset();
+  StopAndDeAllocate();
+}
+#endif  // defined(OS_CHROMEOS)
+
 class AuraWindowVideoCaptureDeviceBrowserTestP
     : public AuraWindowVideoCaptureDeviceBrowserTest,
       public testing::WithParamInterface<std::tuple<bool, bool>> {