Implement handling for MS PowerPoint Presentation Mode.

* Introduce a FullScreenWindowDetector to manage routines for updating the list of sources being application agnostic, inspired by FullScreenChromeWindowDetector.
* Introduce a FullScreenApplicationHandler to make a decision about changing window to share in application specific way, inspired by FullScreenChromeWindowDetector.
* Remove FullScreenChromeWindowDetector as redundant.
* Add FullScreenApplicationHandler for MS PowerPoint and Apple Keynote on MacOS.
* Add FullScreenApplicationHandler for MS PowerPoint on Windows.

Bug: webrtc:3852
Change-Id: I06507d929308e85b882b2f8210a025afef7f26a9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/156020
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Reviewed-by: Justin Uberti <juberti@webrtc.org>
Reviewed-by: Wez <wez@google.com>
Cr-Commit-Position: refs/heads/master@{#29993}

modules/desktop_capture/full_screen_application_handler.cc

@@ -0,0 +1,30 @@
+/*
+ *  Copyright (c) 2019 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 "modules/desktop_capture/full_screen_application_handler.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+FullScreenApplicationHandler::FullScreenApplicationHandler(
+    DesktopCapturer::SourceId sourceId)
+    : source_id_(sourceId) {}
+
+DesktopCapturer::SourceId FullScreenApplicationHandler::FindFullScreenWindow(
+    const DesktopCapturer::SourceList&,
+    int64_t) const {
+  return 0;
+}
+
+DesktopCapturer::SourceId FullScreenApplicationHandler::GetSourceId() const {
+  return source_id_;
+}
+
+}  // namespace webrtc