From 8a8b238556abedf92f69ab680a8bb03af3ed280f Mon Sep 17 00:00:00 2001
From: zijiehe <zijiehe@chromium.org>
Date: Fri, 31 Mar 2017 14:13:40 -0700
Subject: [PATCH] ScreenCapturerWinDirectx should have two
 DxgiDuplicatorController::Context instances, each for one DesktopFrame. So
 both DesktopFrame instances can be correctly updated.

I have verified this change on my laptop, which cannot reproduce the issue anymore.

BUG=704205

Review-Url: https://codereview.webrtc.org/2781253002
Cr-Commit-Position: refs/heads/master@{#17494}
---
 .../win/screen_capturer_win_directx.cc            | 15 +++++++++++----
 .../win/screen_capturer_win_directx.h             |  3 ++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
index 90bdeb6124..36e43fbad7 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
@@ -15,6 +15,7 @@
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
+#include "webrtc/base/ptr_util.h"
 #include "webrtc/base/timeutils.h"
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/win/screen_capture_utils.h"
@@ -106,10 +107,15 @@ void ScreenCapturerWinDirectx::CaptureFrame() {
     }
     frames_.ReplaceCurrentFrame(SharedDesktopFrame::Wrap(std::move(new_frame)));
   }
+  contexts_.MoveToNextFrame();
+  if (!contexts_.current_frame()) {
+    contexts_.ReplaceCurrentFrame(
+        rtc::MakeUnique<DxgiDuplicatorController::Context>());
+  }
 
   if (current_screen_id_ == kFullDesktopScreenId) {
     if (!DxgiDuplicatorController::Instance()->Duplicate(
-            &context_, frames_.current_frame())) {
+            contexts_.current_frame(), frames_.current_frame())) {
       // Screen size may be changed, so we need to reset the frames.
       frames_.Reset();
       resolution_change_detector_.Reset();
@@ -118,7 +124,8 @@ void ScreenCapturerWinDirectx::CaptureFrame() {
     }
   } else {
     if (!DxgiDuplicatorController::Instance()->DuplicateMonitor(
-            &context_, current_screen_id_, frames_.current_frame())) {
+            contexts_.current_frame(), current_screen_id_,
+            frames_.current_frame())) {
       // Screen size may be changed, so we need to reset the frames.
       frames_.Reset();
       resolution_change_detector_.Reset();
@@ -158,14 +165,14 @@ bool ScreenCapturerWinDirectx::SelectSource(SourceId id) {
   // frames only when a Duplicate() function call returns false.
   if (id == kFullDesktopScreenId) {
     current_screen_id_ = id;
-    context_.Reset();
+    contexts_.Reset();
     return true;
   }
 
   int screen_count = DxgiDuplicatorController::Instance()->ScreenCount();
   if (id >= 0 && id < screen_count) {
     current_screen_id_ = id;
-    context_.Reset();
+    contexts_.Reset();
     return true;
   }
   return false;
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
index a48bda9954..82f8be3658 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
@@ -59,10 +59,11 @@ class ScreenCapturerWinDirectx : public DesktopCapturer {
   // Returns desktop size of selected screen.
   DesktopSize SelectedDesktopSize() const;
 
+  // TODO(zijiehe): Merge |frames_| and |contexts_| into a single object.
   ScreenCaptureFrameQueue<SharedDesktopFrame> frames_;
+  ScreenCaptureFrameQueue<DxgiDuplicatorController::Context> contexts_;
   std::unique_ptr<SharedMemoryFactory> shared_memory_factory_;
   Callback* callback_ = nullptr;
-  DxgiDuplicatorController::Context context_;
   SourceId current_screen_id_ = kFullDesktopScreenId;
   ResolutionChangeDetector resolution_change_detector_;