adds WARP support to Chromium, for Metro mode only, on Windows 8

ui/gl/gl_surface_win.cc

 // Copyright (c) 2012 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.h"
 
 #include <dwmapi.h>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/win/windows_version.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gfx/native_widget_types.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_osmesa.h"
 #include "ui/gl/gl_surface_stub.h"
 #include "ui/gl/gl_surface_wgl.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
+#if !defined(EGL_PLATFORM_ANGLE_ANGLE)
+#define EGL_PLATFORM_ANGLE_ANGLE 0x3201
+#endif
+#if !defined(EGL_PLATFORM_ANGLE_TYPE_ANGLE)
+#define EGL_PLATFORM_ANGLE_TYPE_ANGLE 0x3202
+#endif
+#if !defined(EGL_PLATFORM_ANGLE_TYPE_D3D11_WARP_ANGLE)
+#define EGL_PLATFORM_ANGLE_TYPE_D3D11_WARP_ANGLE 0x3206
+#endif
 
 namespace gfx {
 
 // This OSMesa GL surface can use GDI to swap the contents of the buffer to a
 // view.
 class NativeViewGLSurfaceOSMesa : public GLSurfaceOSMesa {
  public:
   explicit NativeViewGLSurfaceOSMesa(gfx::AcceleratedWidget window);
   virtual ~NativeViewGLSurfaceOSMesa();
 
@@ skipping 249 matching lines @@
     }
     case kGLImplementationMockGL:
       return new GLSurfaceStub;
     default:
       NOTREACHED();
       return NULL;
   }
 }
 
 EGLNativeDisplayType GetPlatformDefaultEGLNativeDisplay() {
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableD3D11))
-    return EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE;
-
-  return EGL_DEFAULT_DISPLAY;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableD3D11) ||
+      CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseWarp))
+    return GetDC(NULL);

[Ken Russell (switch to Gerrit), 2014/09/02 23:57:29]

Is GetDC(NULL) the correct return value when --disable-d3d11 is passed? How does
the behavior differ compared to the previous return value of
EGL_DEFAULT_DISPLAY?

[luken, 2014/09/03 00:58:07]

It turns out that ANGLE always wants a valid DeviceContext passed in as the
EGLNativeDisplayType argument to eglGetDisplay(), but the ANGLE code isn't
enforcing the validity check on the DC for that function call. It is, however,
enforcing that validity check for eglGetDisplayEXT(), which we now call in the
case for warp. If you don't specify a platform type you get the default display
which is D3D9. So in the case of disabling d3d11 we are still requesting the
"default" D3D9 display, but in a slightly less invalid way.

+  return EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE;
 }
 
 }  // namespace gfx