Allow WebGL readback for Mesa llvmpipe driver

gpu/config/software_rendering_list_json.cc

 // Copyright (c) 2013 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.
 
 // Determines whether certain gpu-related features are blacklisted or not.
 // The format of a valid software_rendering_list.json file is defined in
 // <gpu/config/gpu_control_list_format.txt>.
 // The supported "features" can be found in <gpu/config/gpu_blacklist.cc>.
 
 #include "gpu/config/gpu_control_list_jsons.h"
 
 #define LONG_STRING_CONST(...) #__VA_ARGS__
 
 namespace gpu {
 
 const char kSoftwareRenderingListJson[] = LONG_STRING_CONST(
 
 {
   "name": "software rendering list",
   // Please update the version number whenever you change this file.
-  "version": "10.18",
+  "version": "10.19",
   "entries": [
     {
       "id": 1,
       "description": "ATI Radeon X1900 is not compatible with WebGL on the Mac",
       "webkit_bugs": [47028],
       "os": {
         "type": "macosx"
       },
       "vendor_id": "0x1002",
       "device_id": ["0x7249"],
@@ skipping 479 matching lines @@
       "device_id": ["0x0fd5"],
       "multi_gpu_category": "any",
       "features": [
         "flash_3d",
         "flash_stage3d"
       ]
     },
     {
       "id": 50,
       "description": "Disable VMware software renderer on older Mesa",
-      "cr_bugs": [145531, 332596],
+      "cr_bugs": [145531, 332596, 571899],
       "os": {
         "type": "linux"
       },
       "gl_vendor": "VMware.*",
       "exceptions": [
         {
-          "driver_vendor": "Mesa",

[piman, 2016/04/14 02:46:14]

Any reason for removing this?

[Julien Isorce Samsung, 2016/04/14 17:54:27]

It is a mistake :)

           "driver_version": {
             "op": ">=",
             "value": "9.2.1"
           },
           "gl_renderer": ".*SVGA3D.*"
+        },
+        {
+          "driver_vendor": "Mesa",
+          "driver_version": {
+            "op": ">=",
+            "value": "10.1.3"
+          },
+          "gl_renderer": ".*Gallium.*llvmpipe.*"
         }
       ],
       "features": [
         "all"
       ]
     },
     {
       "id": 53,
       "description": "The Intel GMA500 is too slow for Stage3D",
       "cr_bugs": [152096],
@@ skipping 661 matching lines @@
         }
       },
       "gl_renderer": "Adreno \\(TM\\) 330",
       "driver_version": {
         "op": "=",
         "value": "45.0"
       },
       "features": [
         "accelerated_video_decode"
       ]
+    },
+    {
+      "id": 110,
+      "description": "Only enable WebGL for the Mesa Gallium llvmpipe driver",
+      "cr_bugs": [571899],
+      "os": {
+        "type": "linux"
+      },
+      "driver_vendor": "Mesa",
+      "gl_vendor": "VMware.*",
+      "gl_renderer": ".*Gallium.*llvmpipe.*",
+      "features": [
+        "accelerated_2d_canvas",
+        "gpu_compositing",
+        "flash_3d",
+        "flash_stage3d",
+        "flash_stage3d_baseline",
+        "accelerated_video_decode",
+        "accelerated_video_encode",
+        "panel_fitting",
+        "gpu_rasterization"

[piman, 2016/04/14 02:46:14]

@zmo: is there a way to do the opposite, disable all features but whitelist
webgl? I worry that this won't be maintained as we add other features.

[Ken Russell (switch to Gerrit), 2016/04/14 02:56:26]

Not to speak for zmo@ but I suspect the JSON file would have to be extended with
an "enabled_features" list whose semantic is the opposite of "features".

[Julien Isorce Samsung, 2016/04/14 17:54:27]

If there is no way to express that (zmo@ ?), and since it would only make sense
to use that whitelist when the "all" keyword is used (if I am not mistaken), I
suggest the following format (instead of "enabled_features"):
all^webgl,accelerated_video_decode,flash_stage3d . So in that CL I would be use:
all^webgl

[Zhenyao Mo, 2016/04/14 20:23:45]

We can implement an "exception" to the "features", so add "all" and enabled
features in the "exception". This should be implemented separately from this CL.

[Julien Isorce Samsung, 2016/04/14 21:10:06]

Thx Zhenyao for your suggestion. But to avoid any confusion, do you mean:

a)

{
  "id": 1,
  "os": {
    "type": "linux"
  },
  "gl_renderer": "*engine*",
  "features": [
    "all",
    "exception": [
      "accelerated_video_decode",
      "webgl"
    ]
  ]
}

or

b)

{
  "id": 2,
  "description": "Some desc2",
  "os": {
  "type": "linux"
  },
  "vendor_id": "0x1002",
  "exceptions": [
    {
      "driver_vendor": ".*AMD.*",
      "features": [
        "webgl",
        "accelerated_video_decode"
      ]
    }
  ],
  "features": [
    "all"
  ]
}

I already thought about b) but it was not possible because of current
implementation of ControlList::MakeDecision + Entry::Contain logic.

But I think what you suggest is something similar to a) but this cannot be
exactly a) because this "features" is a list so it cannot contains a key+val
unless I am mistaken.

So can you provide an example for the format ? Thx.

+      ]
     }
   ]
 }
 
 );  // LONG_STRING_CONST macro
 
 }  // namespace gpu