X11: Use better visuals for OpenGL

gpu/config/gpu_info.h

 // 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.
 
 #ifndef GPU_CONFIG_GPU_INFO_H_
 #define GPU_CONFIG_GPU_INFO_H_
 
 // Provides access to the GPU information for the system
 // on which chrome is currently running.
 
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
 #include "base/time/time.h"
 #include "base/version.h"
 #include "build/build_config.h"
 #include "gpu/config/dx_diag_node.h"
 #include "gpu/gpu_export.h"
 #include "ui/gfx/geometry/size.h"
 
+#if defined(USE_X11) && !defined(OS_CHROMEOS)
+typedef unsigned long VisualID;
+#endif
+
 namespace gpu {
 
 // Result for the various Collect*Info* functions below.
 // Fatal failures are for cases where we can't create a context at all or
 // something, making the use of the GPU impossible.
 // Non-fatal failures are for cases where we could gather most info, but maybe
 // some is missing (e.g. unable to parse a version string or to detect the exact
 // model).
 enum CollectInfoResult {
   kCollectInfoNone = 0,
@@ skipping 196 matching lines @@
 
   // The information returned by the DirectX Diagnostics Tool.
   DxDiagNode dx_diagnostics;
 #endif
 
   VideoDecodeAcceleratorCapabilities video_decode_accelerator_capabilities;
   VideoEncodeAcceleratorSupportedProfiles
       video_encode_accelerator_supported_profiles;
   bool jpeg_decode_accelerator_supported;
 
+#if defined(USE_X11) && !defined(OS_CHROMEOS)
+  VisualID system_visual;
+  VisualID rgba_visual;

[dcheng, 2016/09/27 23:25:51]

Just to help me understand: the GPU sends these IDs back to the browser (which
listened to them with GpuDataManagerVisualProxy), right?

I see these IDs are later consumed in ChooseVisualForWindow as an index. Do we
need to verify that the indices are not out of bounds?

[Tom (Use chromium acct), 2016/09/27 23:47:49]

That's correct
XVisualManager gets all the visuals on creation, and there can't be any more
visuals that get created, so any visual ID the GPU gives should already be
cached by XVisualManager.  If the Gpu process is untrusted (I'm not really
familiar with the security side of this), I can add a check in OnGpuInfoChanged

[Tom (Use chromium acct), 2016/09/28 18:36:01]

Added the check.

+#endif
+
   // Note: when adding new members, please remember to update EnumerateFields
   // in gpu_info.cc.
 
   // In conjunction with EnumerateFields, this allows the embedder to
   // enumerate the values in this structure without having to embed
   // references to its specific member variables. This simplifies the
   // addition of new fields to this type.
   class Enumerator {
    public:
     // The following methods apply to the "current" object. Initially this
@@ skipping 30 matching lines @@
     virtual ~Enumerator() {}
   };
 
   // Outputs the fields in this structure to the provided enumerator.
   void EnumerateFields(Enumerator* enumerator) const;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_CONFIG_GPU_INFO_H_