[PIP] Add picture in picture flag and switch.

chrome/browser/flag_descriptions.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/flag_descriptions.h"
 
 namespace flag_descriptions {
 
 //  Material Design version of chrome://bookmarks
 
@@ skipping 1044 matching lines @@
 
 const char kEnableNavigationTracingName[] = "Enable navigation tracing";
 
 const char kEnableNavigationTracingDescription[] =
     "This is to be used in conjunction with the trace-upload-url flag. "
     "WARNING: When enabled, Chrome will record performance data for every "
     "navigation and upload it to the URL specified by the trace-upload-url "
     "flag. The trace may include personally identifiable information (PII) "
     "such as the titles and URLs of websites you visit.";
 
+const char kEnablePictureInPictureName[] = "Enable picture in picture.";
+
+const char kEnablePictureInPictureDescription[] =
+    "Enable the picture in picture feature for videos.";
+
 const char kTraceUploadUrlName[] = "Trace label for navigation tracing";
 
 const char kTraceUploadUrlDescription[] =
     "This is to be used in conjunction with the enable-navigation-tracing "
     "flag. Please select the label that best describes the recorded traces. "
     "This will choose the destination the traces are uploaded to. If you "
     "are not sure, select other. If left empty, no traces will be "
     "uploaded.";
 
 const char kDisableAudioForDesktopShareName[] =
@@ skipping 2124 matching lines @@
 
 const char kDisableNewVirtualKeyboardBehaviorName[] =
     "New window behavior for the accessibility keyboard";
 const char kDisableNewVirtualKeyboardBehaviorDescription[] =
     "Disable new window behavior for the accessibility keyboard "
     "in non-sticky mode (do not change work area in non-sticky mode).";
 
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace flag_descriptions