Enable cursor compositing during screen capture

This allows desktop capture to also include the mouse cursor without
having to induce a separate compositing stage for desktop capture
itself.

Bug: b:38452042
Change-Id: Ibfa75454ef44b8329d643dcfcc94a1b7b65018e4
Reviewed-on: https://chromium-review.googlesource.com/899606
Commit-Queue: Jeffrey Kardatzke <jkardatzke@google.com>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534215}

ash/display/cursor_window_controller.cc

@@ -120,7 +120,8 @@ bool CursorWindowController::ShouldEnableCursorCompositing() {
   display::DisplayManager* display_manager = Shell::Get()->display_manager();
   if ((display_manager->is_multi_mirroring_enabled() &&
        display_manager->IsInSoftwareMirrorMode()) ||
-      display_manager->IsInUnifiedMode()) {
+      display_manager->IsInUnifiedMode() ||
+      display_manager->screen_capture_is_active()) {
     return true;
   }
 

chrome/browser/chromeos/arc/screen_capture/arc_screen_capture_session.cc

@@ -6,6 +6,7 @@
 
 #include <utility>
 
+#include "ash/shell.h"
 #include "base/bind.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chromeos/ui/screen_capture_notification_ui_chromeos.h"
@@ -29,6 +30,7 @@
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/compositor/dip_util.h"
+#include "ui/display/manager/display_manager.h"
 #include "ui/gfx/gpu_memory_buffer.h"
 
 namespace {
@@ -133,6 +135,9 @@ mojom::ScreenCaptureSessionPtr ArcScreenCaptureSession::Initialize(
       base::BindRepeating(&ArcScreenCaptureSession::NotificationStop,
                           weak_ptr_factory_.GetWeakPtr()));
 
+  ash::Shell::Get()->display_manager()->inc_screen_capture_active_counter();
+  ash::Shell::Get()->UpdateCursorCompositingEnabled();
+
   mojom::ScreenCaptureSessionPtr interface_ptr;
   binding_.Bind(mojo::MakeRequest(&interface_ptr));
   binding_.set_connection_error_handler(
@@ -147,6 +152,8 @@ void ArcScreenCaptureSession::Close() {
 
 ArcScreenCaptureSession::~ArcScreenCaptureSession() {
   desktop_window_->GetHost()->compositor()->RemoveAnimationObserver(this);
+  ash::Shell::Get()->display_manager()->dec_screen_capture_active_counter();
+  ash::Shell::Get()->UpdateCursorCompositingEnabled();
 }
 
 void ArcScreenCaptureSession::NotificationStop() {

ui/display/manager/display_manager.h

@@ -8,6 +8,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include <algorithm>
 #include <map>
 #include <memory>
 #include <string>
@@ -16,6 +17,7 @@
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
+#include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ -354,6 +356,17 @@ class DISPLAY_MANAGER_EXPORT DisplayManager
     mixed_mirror_mode_params_ = mixed_params;
   }
 
+  void dec_screen_capture_active_counter() {
+    DCHECK_GT(screen_capture_active_counter_, 0);
+    screen_capture_active_counter_--;
+  }
+
+  void inc_screen_capture_active_counter() { ++screen_capture_active_counter_; }
+
+  bool screen_capture_is_active() const {
+    return screen_capture_active_counter_ > 0;
+  }
+
   // Remove mirroring source and destination displays, so that they will be
   // updated when UpdateDisplaysWith() is called.
   void ClearMirroringSourceAndDestination();
@@ -646,6 +659,10 @@ class DISPLAY_MANAGER_EXPORT DisplayManager
 
   bool internal_display_has_accelerometer_ = false;
 
+  // Set during screen capture to enable software compositing of mouse cursor,
+  // this is a counter to enable multiple active sessions at once.
+  int screen_capture_active_counter_ = 0;
+
   base::Closure created_mirror_window_;
 
   base::ObserverList<DisplayObserver> observers_;