Replace NULL with nullptr in all C++ files.

webrtc/modules/desktop_capture/win/cursor_unittest.cc

Index: webrtc/modules/desktop_capture/win/cursor_unittest.cc
diff --git a/webrtc/modules/desktop_capture/win/cursor_unittest.cc b/webrtc/modules/desktop_capture/win/cursor_unittest.cc
index e37fd981b04575e753e8508f3ccee1a55b04a498..b09e84cf7304b49da79ea10db6a3b1fc855bb75f 100644
--- a/webrtc/modules/desktop_capture/win/cursor_unittest.cc
+++ b/webrtc/modules/desktop_capture/win/cursor_unittest.cc
@@ -26,18 +26,18 @@ namespace {
 // compares pixels with |right|. Returns true of MouseCursor bits match |right|.
 // |right| must be a 32bpp cursor with alpha channel.
 bool ConvertToMouseShapeAndCompare(unsigned left, unsigned right) {
-  HMODULE instance = GetModuleHandle(NULL);
+  HMODULE instance = GetModuleHandle(nullptr);
 
   // Load |left| from the EXE module's resources.
   win::ScopedCursor cursor(reinterpret_cast<HCURSOR>(
       LoadImage(instance, MAKEINTRESOURCE(left), IMAGE_CURSOR, 0, 0, 0)));
-  EXPECT_TRUE(cursor != NULL);
+  EXPECT_TRUE(cursor != nullptr);
 
   // Convert |cursor| to |mouse_shape|.
-  HDC dc = GetDC(NULL);
+  HDC dc = GetDC(nullptr);
   std::unique_ptr<MouseCursor> mouse_shape(
       CreateMouseCursorFromHCursor(dc, cursor));
-  ReleaseDC(NULL, dc);
+  ReleaseDC(nullptr, dc);
 
   EXPECT_TRUE(mouse_shape.get());