Use PrintWindow() to implement snapshots on windows 8.1+

ui/gl/gl_surface_osmesa_win.cc

 // Copyright 2016 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 "ui/gl/gl_surface_osmesa_win.h"
 
 #include <memory>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/trace_event/trace_event.h"
 #include "base/win/windows_version.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface_egl.h"
 #include "ui/gl/gl_surface_wgl.h"
 #include "ui/gl/vsync_provider_win.h"
 
 // From ANGLE's egl/eglext.h.
 #if !defined(EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE)
 #define EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE \
   reinterpret_cast<EGLNativeDisplayType>(-2)
 #endif
 
 namespace gl {
 
+// Use BGRA, because StretchDIBits from RGBA causes later PrintWindow or
+// BitBlt from the HWND to return all 0s, which causes the snapshot mechanism
+// not to work.
 GLSurfaceOSMesaWin::GLSurfaceOSMesaWin(gfx::AcceleratedWidget window)
-    : GLSurfaceOSMesa(GLSurfaceFormat(GLSurfaceFormat::PIXEL_LAYOUT_RGBA),
+    : GLSurfaceOSMesa(GLSurfaceFormat(GLSurfaceFormat::PIXEL_LAYOUT_BGRA),
                       gfx::Size(1, 1)),
       window_(window),
       device_context_(NULL) {
   DCHECK(window);
 }
 
 GLSurfaceOSMesaWin::~GLSurfaceOSMesaWin() {
   Destroy();
 }
 
@@ skipping 15 matching lines @@
 }
 
 bool GLSurfaceOSMesaWin::IsOffscreen() {
   return false;
 }
 
 gfx::SwapResult GLSurfaceOSMesaWin::SwapBuffers() {
   DCHECK(device_context_);
 
   gfx::Size size = GetSize();
-
-  // Note: negating the height below causes GDI to treat the bitmap data as row
-  // 0 being at the top.
-  BITMAPV4HEADER info = {sizeof(BITMAPV4HEADER)};
-  info.bV4Width = size.width();
-  info.bV4Height = -size.height();
-  info.bV4Planes = 1;
-  info.bV4BitCount = 32;
-  info.bV4V4Compression = BI_BITFIELDS;
-  info.bV4RedMask = 0x000000FF;
-  info.bV4GreenMask = 0x0000FF00;
-  info.bV4BlueMask = 0x00FF0000;
-  info.bV4AlphaMask = 0xFF000000;
-
-  // Copy the back buffer to the window's device context. Do not check whether
-  // StretchDIBits succeeds or not. It will fail if the window has been
-  // destroyed but it is preferable to allow rendering to silently fail if the
-  // window is destroyed. This is because the primary application of this
-  // class of GLContext is for testing and we do not want every GL related ui /
-  // browser test to become flaky if there is a race condition between GL
-  // context destruction and window destruction.
-  StretchDIBits(device_context_, 0, 0, size.width(), size.height(), 0, 0,
-                size.width(), size.height(), GetHandle(),
-                reinterpret_cast<BITMAPINFO*>(&info), DIB_RGB_COLORS, SRCCOPY);
-
-  return gfx::SwapResult::SWAP_ACK;
+  return PostSubBuffer(0, 0, size.width(), size.height());
 }
 
 bool GLSurfaceOSMesaWin::SupportsPostSubBuffer() {
   return true;
 }
 
 gfx::SwapResult GLSurfaceOSMesaWin::PostSubBuffer(int x,
                                                   int y,
                                                   int width,
                                                   int height) {
   DCHECK(device_context_);
 
   gfx::Size size = GetSize();
 
   // Note: negating the height below causes GDI to treat the bitmap data as row
   // 0 being at the top.
   BITMAPV4HEADER info = {sizeof(BITMAPV4HEADER)};
   info.bV4Width = size.width();
   info.bV4Height = -size.height();
   info.bV4Planes = 1;
   info.bV4BitCount = 32;
   info.bV4V4Compression = BI_BITFIELDS;
-  info.bV4RedMask = 0x000000FF;
+  info.bV4RedMask = 0x00FF0000;
   info.bV4GreenMask = 0x0000FF00;
-  info.bV4BlueMask = 0x00FF0000;
+  info.bV4BlueMask = 0x000000FF;
   info.bV4AlphaMask = 0xFF000000;
 
   // Copy the back buffer to the window's device context. Do not check whether
   // StretchDIBits succeeds or not. It will fail if the window has been
   // destroyed but it is preferable to allow rendering to silently fail if the
   // window is destroyed. This is because the primary application of this
   // class of GLContext is for testing and we do not want every GL related ui /
   // browser test to become flaky if there is a race condition between GL
   // context destruction and window destruction.
   StretchDIBits(device_context_, x, size.height() - y - height, width, height,
                 x, y, width, height, GetHandle(),
                 reinterpret_cast<BITMAPINFO*>(&info), DIB_RGB_COLORS, SRCCOPY);
 
   return gfx::SwapResult::SWAP_ACK;
 }
 
 }  // namespace gl