Remove window style PWS_CHILD

As of the previous CL, it no longer changes any behaviours.

Change-Id: I4e2471e63c89ccb7740f230c63e78b95fa424013
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/79521
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

fpdfsdk/pwl/cpwl_combo_box.cpp

diff --git a/fpdfsdk/pwl/cpwl_combo_box.cpp b/fpdfsdk/pwl/cpwl_combo_box.cpp
index efe5374..9b83705 100644
--- a/fpdfsdk/pwl/cpwl_combo_box.cpp
+++ b/fpdfsdk/pwl/cpwl_combo_box.cpp
@@ -139,8 +139,8 @@
     return;
 
   CreateParams ecp = cp;
-  ecp.dwFlags = PWS_VISIBLE | PWS_CHILD | PWS_BORDER | PES_CENTER |
-                PES_AUTOSCROLL | PES_UNDO;
+  ecp.dwFlags =
+      PWS_VISIBLE | PWS_BORDER | PES_CENTER | PES_AUTOSCROLL | PES_UNDO;
 
   if (HasFlag(PWS_AUTOFONTSIZE))
     ecp.dwFlags |= PWS_AUTOFONTSIZE;
@@ -164,7 +164,7 @@
     return;
 
   CreateParams bcp = cp;
-  bcp.dwFlags = PWS_VISIBLE | PWS_CHILD | PWS_BORDER | PWS_BACKGROUND;
+  bcp.dwFlags = PWS_VISIBLE | PWS_BORDER | PWS_BACKGROUND;
   bcp.sBackgroundColor = CFX_Color(CFX_Color::kRGB, 220.0f / 255.0f,
                                    220.0f / 255.0f, 220.0f / 255.0f);
   bcp.sBorderColor = PWL_DEFAULT_BLACKCOLOR;
@@ -183,8 +183,7 @@
     return;
 
   CreateParams lcp = cp;
-  lcp.dwFlags =
-      PWS_CHILD | PWS_BORDER | PWS_BACKGROUND | PLBS_HOVERSEL | PWS_VSCROLL;
+  lcp.dwFlags = PWS_BORDER | PWS_BACKGROUND | PLBS_HOVERSEL | PWS_VSCROLL;
   lcp.nBorderStyle = BorderStyle::kSolid;
   lcp.dwBorderWidth = 1;
   lcp.eCursorType = FXCT_ARROW;

fpdfsdk/pwl/cpwl_edit.cpp

diff --git a/fpdfsdk/pwl/cpwl_edit.cpp b/fpdfsdk/pwl/cpwl_edit.cpp
index 41d68b0..d8dec00 100644
--- a/fpdfsdk/pwl/cpwl_edit.cpp
+++ b/fpdfsdk/pwl/cpwl_edit.cpp
@@ -523,7 +523,7 @@
     return;
 
   CreateParams ecp = cp;
-  ecp.dwFlags = PWS_CHILD | PWS_NOREFRESHCLIP;
+  ecp.dwFlags = PWS_NOREFRESHCLIP;
   ecp.dwBorderWidth = 0;
   ecp.nBorderStyle = BorderStyle::kSolid;
   ecp.rcRectWnd = CFX_FloatRect();

fpdfsdk/pwl/cpwl_scroll_bar.cpp

diff --git a/fpdfsdk/pwl/cpwl_scroll_bar.cpp b/fpdfsdk/pwl/cpwl_scroll_bar.cpp
index 7ed8f8c..2e47f1b 100644
--- a/fpdfsdk/pwl/cpwl_scroll_bar.cpp
+++ b/fpdfsdk/pwl/cpwl_scroll_bar.cpp
@@ -287,8 +287,7 @@
   CreateParams scp = cp;
   scp.dwBorderWidth = 2;
   scp.nBorderStyle = BorderStyle::kBeveled;
-  scp.dwFlags =
-      PWS_VISIBLE | PWS_CHILD | PWS_BORDER | PWS_BACKGROUND | PWS_NOREFRESHCLIP;
+  scp.dwFlags = PWS_VISIBLE | PWS_BORDER | PWS_BACKGROUND | PWS_NOREFRESHCLIP;
 
   if (!m_pMinButton) {
     auto pButton = std::make_unique<CPWL_SBButton>(

fpdfsdk/pwl/cpwl_wnd.cpp

diff --git a/fpdfsdk/pwl/cpwl_wnd.cpp b/fpdfsdk/pwl/cpwl_wnd.cpp
index 0eb4e59..3de9af9 100644
--- a/fpdfsdk/pwl/cpwl_wnd.cpp
+++ b/fpdfsdk/pwl/cpwl_wnd.cpp
@@ -474,8 +474,7 @@
     return;
 
   CreateParams scp = cp;
-  scp.dwFlags =
-      PWS_CHILD | PWS_BACKGROUND | PWS_AUTOTRANSPARENT | PWS_NOREFRESHCLIP;
+  scp.dwFlags = PWS_BACKGROUND | PWS_AUTOTRANSPARENT | PWS_NOREFRESHCLIP;
   scp.sBackgroundColor = PWL_DEFAULT_WHITECOLOR;
   scp.eCursorType = FXCT_ARROW;
   scp.nTransparency = PWL_SCROLLBAR_TRANSPARENCY;

fpdfsdk/pwl/cpwl_wnd.h

diff --git a/fpdfsdk/pwl/cpwl_wnd.h b/fpdfsdk/pwl/cpwl_wnd.h
index 0029ab5..583ef5b 100644
--- a/fpdfsdk/pwl/cpwl_wnd.h
+++ b/fpdfsdk/pwl/cpwl_wnd.h
@@ -25,7 +25,6 @@
 struct PWL_SCROLL_INFO;
 
 // window styles
-#define PWS_CHILD 0x80000000L
 #define PWS_BORDER 0x40000000L
 #define PWS_BACKGROUND 0x20000000L
 #define PWS_VSCROLL 0x08000000L