Modify ScreenCaptureFrameQueue into a template

webrtc/modules/desktop_capture/screen_capturer_x11.cc

Index: webrtc/modules/desktop_capture/screen_capturer_x11.cc
diff --git a/webrtc/modules/desktop_capture/screen_capturer_x11.cc b/webrtc/modules/desktop_capture/screen_capturer_x11.cc
index 65e682b6f8bdc1bd28ba99d515077122fc105adb..849d1a3802401961b85b7c3a171f677507e7cfae 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_x11.cc
+++ b/webrtc/modules/desktop_capture/screen_capturer_x11.cc
@@ -24,8 +24,9 @@
 #include "webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/differ.h"
-#include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
+#include "webrtc/modules/desktop_capture/screen_capture_queue.h"
 #include "webrtc/modules/desktop_capture/screen_capturer_helper.h"
+#include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
 #include "webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.h"
 #include "webrtc/system_wrappers/include/logging.h"
 #include "webrtc/system_wrappers/include/tick_util.h"
@@ -106,7 +107,7 @@ class ScreenCapturerLinux : public ScreenCapturer,
   ScreenCapturerHelper helper_;
 
   // Queue of the frames buffers.
-  ScreenCaptureFrameQueue queue_;
+  ScreenCaptureQueue<SharedDesktopFrame> queue_;
 
   // Invalid region from the previous capture. This is used to synchronize the
   // current with the last buffer used.
@@ -236,7 +237,8 @@ void ScreenCapturerLinux::Start(Callback* callback) {
 void ScreenCapturerLinux::Capture(const DesktopRegion& region) {
   TickTime capture_start_time = TickTime::Now();
 
-  queue_.MoveToNextFrame();
+  queue_.MoveToNext();
+  RTC_DCHECK(!queue_.current() || !queue_.current()->IsShared());
 
   // Process XEvents for XDamage and cursor shape tracking.
   options_.x_display()->ProcessPendingXEvents();
@@ -253,14 +255,14 @@ void ScreenCapturerLinux::Capture(const DesktopRegion& region) {
   // If the current frame is from an older generation then allocate a new one.
   // Note that we can't reallocate other buffers at this point, since the caller
   // may still be reading from them.
-  if (!queue_.current_frame()) {
+  if (!queue_.current()) {
     std::unique_ptr<DesktopFrame> frame(
         new BasicDesktopFrame(x_server_pixel_buffer_.window_size()));
-    queue_.ReplaceCurrentFrame(frame.release());
+    queue_.ReplaceCurrent(SharedDesktopFrame::Wrap(std::move(frame)));
   }
 
   // Refresh the Differ helper used by CaptureFrame(), if needed.
-  DesktopFrame* frame = queue_.current_frame();
+  DesktopFrame* frame = queue_.current();
   if (!use_damage_ && (
       !differ_.get() ||
       (differ_->width() != frame->size().width()) ||
@@ -308,7 +310,7 @@ bool ScreenCapturerLinux::HandleXEvent(const XEvent& event) {
 }
 
 DesktopFrame* ScreenCapturerLinux::CaptureScreen() {
-  DesktopFrame* frame = queue_.current_frame()->Share();
+  DesktopFrame* frame = queue_.current()->Share();
   assert(x_server_pixel_buffer_.window_size().equals(frame->size()));
 
   // Pass the screen size to the helper, so it can clip the invalid region if it
@@ -319,13 +321,13 @@ DesktopFrame* ScreenCapturerLinux::CaptureScreen() {
   // if any.  If there isn't a previous frame, that means a screen-resolution
   // change occurred, and |invalid_rects| will be updated to include the whole
   // screen.
-  if (use_damage_ && queue_.previous_frame())
+  if (use_damage_ && queue_.previous())
     SynchronizeFrame();
 
   DesktopRegion* updated_region = frame->mutable_updated_region();
 
   x_server_pixel_buffer_.Synchronize();
-  if (use_damage_ && queue_.previous_frame()) {
+  if (use_damage_ && queue_.previous()) {
     // Atomically fetch and clear the damage region.
     XDamageSubtract(display(), damage_handle_, None, damage_region_);
     int rects_num = 0;
@@ -358,12 +360,12 @@ DesktopFrame* ScreenCapturerLinux::CaptureScreen() {
     DesktopRect screen_rect = DesktopRect::MakeSize(frame->size());
     x_server_pixel_buffer_.CaptureRect(screen_rect, frame);
 
-    if (queue_.previous_frame()) {
+    if (queue_.previous()) {
       // Full-screen polling, so calculate the invalid rects here, based on the
       // changed pixels between current and previous buffers.
       RTC_DCHECK(differ_.get() != NULL);
-      RTC_DCHECK(queue_.previous_frame()->data());
-      differ_->CalcDirtyRegion(queue_.previous_frame()->data(),
+      RTC_DCHECK(queue_.previous()->data());
+      differ_->CalcDirtyRegion(queue_.previous()->data(),
                                frame->data(), updated_region);
     } else {
       // No previous buffer, so always invalidate the whole screen, whether
@@ -397,10 +399,10 @@ void ScreenCapturerLinux::SynchronizeFrame() {
   // TODO(hclam): We can reduce the amount of copying here by subtracting
   // |capturer_helper_|s region from |last_invalid_region_|.
   // http://crbug.com/92354
-  RTC_DCHECK(queue_.previous_frame());
+  RTC_DCHECK(queue_.previous());
 
-  DesktopFrame* current = queue_.current_frame();
-  DesktopFrame* last = queue_.previous_frame();
+  DesktopFrame* current = queue_.current();
+  DesktopFrame* last = queue_.previous();
   RTC_DCHECK(current != last);
   for (DesktopRegion::Iterator it(last_invalid_region_);
        !it.IsAtEnd(); it.Advance()) {