Linux: fix XRENDER support for NX

chrome/common/x11_util.cc

 // Copyright (c) 2009 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.
 
 // This file defines utility functions for X11 (Linux only). This code has been
 // ported from XCB since we can't use XCB on Ubuntu while its 32-bit support
 // remains woefully incomplete.
 
 #include "chrome/common/x11_util.h"
 #include "chrome/common/x11_util_internal.h"
@@ skipping 116 matching lines @@
   templ.direct.alphaMask = 0;
 
   static const unsigned long kMask =
     PictFormatType | PictFormatDepth |
     PictFormatRed | PictFormatRedMask |
     PictFormatGreen | PictFormatGreenMask |
     PictFormatBlue | PictFormatBlueMask |
     PictFormatAlphaMask;
 
   pictformat = XRenderFindFormat(dpy, kMask, &templ, 0 /* first result */);
-  CHECK(pictformat) << "XRENDER doesn't not support a Skia compatable format";
-  // TODO(agl): fallback to a picture format with an alpha channel
+
+  if (!pictformat) {
+    // Not all X servers support xRGB32 formats. However, the XRENDER spec says
+    // that they must support an ARGB32 format, so we can always return that.
+    pictformat = XRenderFindStandardFormat(dpy, PictStandardARGB32);
+    CHECK(pictformat) << "XRENDER ARGB32 not supported.";
+  }
 
   return pictformat;
 }
 
 XID AttachSharedMemory(Display* display, int shared_memory_key) {
   DCHECK(QuerySharedMemorySupport(display));
 
   XShmSegmentInfo shminfo;
   memset(&shminfo, 0, sizeof(shminfo));
   shminfo.shmid = shared_memory_key;
@@ skipping 27 matching lines @@
 
 void FreePicture(Display* display, XID picture) {
   XRenderFreePicture(display, picture);
 }
 
 void FreePixmap(Display* display, XID pixmap) {
   XFreePixmap(display, pixmap);
 }
 
 }  // namespace x11_util