[WebRTC] Add ScreenCapturerDifferWrapper to share Differ across ScreenCapturers

webrtc/modules/desktop_capture/BUILD.gn

Index: webrtc/modules/desktop_capture/BUILD.gn
diff --git a/webrtc/modules/desktop_capture/BUILD.gn b/webrtc/modules/desktop_capture/BUILD.gn
index 672433e32b444b68c2c181f05045c48d400c8e0d..36dfb8b0cdbaaf7616c1bd4a1af7b4bebaa945f4 100644
--- a/webrtc/modules/desktop_capture/BUILD.gn
+++ b/webrtc/modules/desktop_capture/BUILD.gn
@@ -62,6 +62,8 @@ source_set("desktop_capture") {
     "mouse_cursor_monitor_win.cc",
     "screen_capture_frame_queue.h",
     "screen_capturer.h",
+    "screen_capturer_differ_wrapper.cc",
+    "screen_capturer_differ_wrapper.h",
     "screen_capturer_helper.cc",
     "screen_capturer_helper.h",
     "screen_capturer_mac.mm",
@@ -170,8 +172,8 @@ if (use_desktop_capture_differ_sse2) {
   source_set("desktop_capture_differ_sse2") {
     visibility = [ ":*" ]
     sources = [
-      "differ_block_sse2.cc",
-      "differ_block_sse2.h",
+      "differ_vector_sse2.cc",
+      "differ_vector_sse2.h",
     ]
 
     configs += [ "../..:common_config" ]