Output DeviceName from various windows ScreenCapturer related implementations

Both DXGI_OUTPUT_DESC and DISPLAY_DEVICE contain the DeviceName, which may be
able to map a DirectX screen id with the GDI screen id.
So this change exports the field from both DirectX and GDI implementations.

BUG=webrtc:7950

Review-Url: https://codereview.webrtc.org/2971393002
Cr-Commit-Position: refs/heads/master@{#19010}

webrtc/modules/desktop_capture/BUILD.gn

@@ -88,6 +88,7 @@ if (rtc_include_tests) {
       "win/cursor_unittest.cc",
       "win/cursor_unittest_resources.h",
       "win/cursor_unittest_resources.rc",
+      "win/screen_capture_utils_unittest.cc",
     ]
     deps = [
       ":desktop_capture",

webrtc/modules/desktop_capture/win/dxgi_adapter_duplicator.cc

@@ -146,6 +146,11 @@ DesktopRect DxgiAdapterDuplicator::ScreenRect(int id) const {
   return duplicators_[id].desktop_rect();
 }
 
+const std::string& DxgiAdapterDuplicator::GetDeviceName(int id) const {
+  RTC_DCHECK(id >= 0 && id < static_cast<int>(duplicators_.size()));
+  return duplicators_[id].device_name();
+}
+
 int DxgiAdapterDuplicator::screen_count() const {
   return static_cast<int>(duplicators_.size());
 }

webrtc/modules/desktop_capture/win/dxgi_adapter_duplicator.h

@@ -59,6 +59,10 @@ class DxgiAdapterDuplicator {
   // should be between [0, screen_count()).
   DesktopRect ScreenRect(int id) const;
 
+  // Returns the device name of one screen owned by this DxgiAdapterDuplicator
+  // in utf8 encoding. |id| should be between [0, screen_count()).
+  const std::string& GetDeviceName(int id) const;
+
   // Returns the count of screens owned by this DxgiAdapterDuplicator. These
   // screens can be retrieved by an interger in the range of
   // [0, screen_count()).

webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.cc

@@ -114,6 +114,16 @@ int DxgiDuplicatorController::ScreenCount() {
   return 0;
 }
 
+bool DxgiDuplicatorController::GetDeviceNames(
+    std::vector<std::string>* output) {
+  rtc::CritScope lock(&lock_);
+  if (Initialize()) {
+    GetDeviceNamesUnlocked(output);
+    return true;
+  }
+  return false;
+}
+
 DxgiDuplicatorController::Result
 DxgiDuplicatorController::DoDuplicate(DxgiFrame* frame, int monitor_id) {
   RTC_DCHECK(frame);
@@ -370,6 +380,16 @@ int DxgiDuplicatorController::ScreenCountUnlocked() const {
   return result;
 }
 
+void DxgiDuplicatorController::GetDeviceNamesUnlocked(
+    std::vector<std::string>* output) const {
+  RTC_DCHECK(output);
+  for (auto& duplicator : duplicators_) {
+    for (int i = 0; i < duplicator.screen_count(); i++) {
+      output->push_back(duplicator.GetDeviceName(i));
+    }
+  }
+}
+
 DesktopSize DxgiDuplicatorController::SelectedDesktopSize(
     int monitor_id) const {
   if (monitor_id < 0) {

webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h

@@ -14,6 +14,7 @@
 #include <D3DCommon.h>
 
 #include <atomic>
+#include <string>
 #include <vector>
 
 #include "webrtc/modules/desktop_capture/desktop_geometry.h"
@@ -101,6 +102,12 @@ class DxgiDuplicatorController {
   // support DXGI based capturer, this function returns 0.
   int ScreenCount();
 
+  // Returns the device names of all screens on the system in utf8 encoding.
+  // These screens can be retrieved by an integer in the range of
+  // [0, output->size()). If system does not support DXGI based capturer, this
+  // function returns false.
+  bool GetDeviceNames(std::vector<std::string>* output);
+
  private:
   // DxgiFrameContext calls private Unregister(Context*) function in Reset().
   friend void DxgiFrameContext::Reset();
@@ -182,6 +189,8 @@ class DxgiDuplicatorController {
 
   int ScreenCountUnlocked() const;
 
+  void GetDeviceNamesUnlocked(std::vector<std::string>* output) const;
+
   // Returns the desktop size of the selected screen |monitor_id|. Setting
   // |monitor_id| < 0 to return the entire screen size.
   DesktopSize SelectedDesktopSize(int monitor_id) const;

webrtc/modules/desktop_capture/win/dxgi_output_duplicator.cc

@@ -23,6 +23,7 @@
 #include "webrtc/modules/desktop_capture/win/dxgi_texture_staging.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/logging.h"
+#include "webrtc/rtc_base/win32.h"
 
 namespace webrtc {
 
@@ -64,6 +65,7 @@ DxgiOutputDuplicator::DxgiOutputDuplicator(const D3dDevice& device,
                                            const DXGI_OUTPUT_DESC& desc)
     : device_(device),
       output_(output),
+      device_name_(rtc::ToUtf8(desc.DeviceName)),
       desktop_rect_(RECTToDesktopRect(desc.DesktopCoordinates)) {
   RTC_DCHECK(output_);
   RTC_DCHECK(!desktop_rect_.is_empty());

webrtc/modules/desktop_capture/win/dxgi_output_duplicator.h

@@ -17,6 +17,7 @@
 #include <DXGI1_2.h>
 
 #include <memory>
+#include <string>
 #include <vector>
 
 #include "webrtc/modules/desktop_capture/desktop_frame_rotation.h"
@@ -68,6 +69,9 @@ class DxgiOutputDuplicator {
   // Returns the desktop rect covered by this DxgiOutputDuplicator.
   DesktopRect desktop_rect() const { return desktop_rect_; }
 
+  // Returns the device name from DXGI_OUTPUT_DESC in utf8 encoding.
+  const std::string& device_name() const { return device_name_; }
+
   void Setup(Context* context);
 
   void Unregister(const Context* const context);
@@ -112,6 +116,7 @@ class DxgiOutputDuplicator {
 
   const D3dDevice device_;
   const Microsoft::WRL::ComPtr<IDXGIOutput1> output_;
+  const std::string device_name_;
   DesktopRect desktop_rect_;
   Microsoft::WRL::ComPtr<IDXGIOutputDuplication> duplication_;
   DXGI_OUTDUPL_DESC desc_;

webrtc/modules/desktop_capture/win/screen_capture_utils.cc

@@ -13,11 +13,16 @@
 #include <windows.h>
 
 #include "webrtc/rtc_base/checks.h"
+#include "webrtc/rtc_base/win32.h"
 
 namespace webrtc {
 
-bool GetScreenList(DesktopCapturer::SourceList* screens) {
-  RTC_DCHECK(screens->size() == 0);
+bool GetScreenList(DesktopCapturer::SourceList* screens,
+                   std::vector<std::string>* device_names /* = nullptr */) {
+  RTC_DCHECK_EQ(screens->size(), 0U);
+  if (device_names) {
+    RTC_DCHECK_EQ(device_names->size(), 0U);
+  }
 
   BOOL enum_result = TRUE;
   for (int device_index = 0;; ++device_index) {
@@ -34,6 +39,9 @@ bool GetScreenList(DesktopCapturer::SourceList* screens) {
       continue;
 
     screens->push_back({device_index, std::string()});
+    if (device_names) {
+      device_names->push_back(rtc::ToUtf8(device.DeviceName));
+    }
   }
   return true;
 }

webrtc/modules/desktop_capture/win/screen_capture_utils.h

@@ -11,13 +11,20 @@
 #ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURE_UTILS_H_
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURE_UTILS_H_
 
+#include <vector>
+#include <string>
+
 #include "webrtc/modules/desktop_capture/desktop_capturer.h"
 
 namespace webrtc {
 
 // Output the list of active screens into |screens|. Returns true if succeeded,
-// or false if it fails to enumerate the display devices.
-bool GetScreenList(DesktopCapturer::SourceList* screens);
+// or false if it fails to enumerate the display devices. If the |device_names|
+// is provided, it will be filled with the DISPLAY_DEVICE.DeviceName in UTF-8
+// encoding. Once this function returns true, consumers can always assume that
+// |screens|[i] and |device_names|[i] indicate the same monitor on the system.
+bool GetScreenList(DesktopCapturer::SourceList* screens,
+                   std::vector<std::string>* device_names = nullptr);
 
 // Returns true if |screen| is a valid screen. The screen device key is
 // returned through |device_key| if the screen is valid. The device key can be

webrtc/modules/desktop_capture/win/screen_capture_utils_unittest.cc

@@ -0,0 +1,32 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/desktop_capture/win/screen_capture_utils.h"
+
+#include <vector>
+#include <string>
+
+#include "webrtc/modules/desktop_capture/desktop_capturer.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+TEST(ScreenCaptureUtilsTest, GetScreenList) {
+  DesktopCapturer::SourceList screens;
+  std::vector<std::string> device_names;
+
+  GetScreenList(&screens);
+  screens.clear();
+  GetScreenList(&screens, &device_names);
+
+  ASSERT_EQ(screens.size(), device_names.size());
+}
+
+}  // namespace webrtc