Deflaky ScreenCapturerTest

webrtc/modules/desktop_capture/screen_drawer.h

Index: webrtc/modules/desktop_capture/screen_drawer.h
diff --git a/webrtc/modules/desktop_capture/screen_drawer.h b/webrtc/modules/desktop_capture/screen_drawer.h
index d7ec5d186cb7896cb9a16336289b27eb33d1467b..76ea94a862bb9f4c2648f5f1e57e7de9745f8b6d 100644
--- a/webrtc/modules/desktop_capture/screen_drawer.h
+++ b/webrtc/modules/desktop_capture/screen_drawer.h
@@ -26,6 +26,9 @@ class ScreenDrawer {
  public:
   // Creates a ScreenDrawer for the current platform, returns nullptr if no
   // ScreenDrawer implementation available.
+  // If the implementation cannot guarantee two ScreenDrawer instances won't
+  // impact each other, this function may block current thread until another
+  // ScreenDrawer has been destroyed.
   static std::unique_ptr<ScreenDrawer> Create();
 
   ScreenDrawer() {}
@@ -49,6 +52,12 @@ class ScreenDrawer {
   // ScreenCapturer should be able to capture the changes after this function
   // finish.
   virtual void WaitForPendingDraws() = 0;
+
+  // Returns true if incomplete shapes previous actions required may be drawn on
+  // the screen after a WaitForPendingDraws() call. i.e. Though the complete
+  // shapes will eventually be drawn on the screen, due to some OS limitations,
+  // these shapes may be partially appeared sometimes.
+  virtual bool MayDrawIncompleteShapes() = 0;
 };
 
 }  // namespace webrtc