Allow WebGL readback for Mesa llvmpipe driver

gpu/config/gpu_info_collector.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 "gpu/config/gpu_info_collector.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/trace_event/trace_event.h"
+#include "gpu/config/gpu_switches.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_version_info.h"
 
 namespace {
 
 scoped_refptr<gfx::GLSurface> InitializeGLSurface() {
   scoped_refptr<gfx::GLSurface> surface(
@@ skipping 80 matching lines @@
   }
 
   scoped_refptr<gfx::GLContext> context(InitializeGLContext(surface.get()));
   if (!context.get()) {
     LOG(ERROR) << "Could not create context for info collection.";
     return kCollectInfoFatalFailure;
   }
 
   gpu_info->gl_renderer = GetGLString(GL_RENDERER);
   gpu_info->gl_vendor = GetGLString(GL_VENDOR);
+  gpu_info->gl_version = GetGLString(GL_VERSION);
+
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kGpuTestingGLVendor)) {
+    gpu_info->gl_vendor =
+        command_line->GetSwitchValueASCII(switches::kGpuTestingGLVendor);
+  }
+  if (command_line->HasSwitch(switches::kGpuTestingGLRenderer)) {
+    gpu_info->gl_renderer =
+        command_line->GetSwitchValueASCII(switches::kGpuTestingGLRenderer);
+  }
+  if (command_line->HasSwitch(switches::kGpuTestingGLVersion)) {
+    gpu_info->gl_version =
+        command_line->GetSwitchValueASCII(switches::kGpuTestingGLVersion);
+  }
+
   gpu_info->gl_extensions = gfx::GetGLExtensionsFromCurrentContext();
-  gpu_info->gl_version = GetGLString(GL_VERSION);
   std::string glsl_version_string = GetGLString(GL_SHADING_LANGUAGE_VERSION);
 
   gfx::GLVersionInfo gl_info(gpu_info->gl_version.c_str(),
                              gpu_info->gl_renderer.c_str(),
                              gpu_info->gl_extensions.c_str());
   GLint max_samples = 0;
   if (gl_info.IsAtLeastGL(3, 0) || gl_info.IsAtLeastGLES(3, 0) ||
       gpu_info->gl_extensions.find("GL_ANGLE_framebuffer_multisample") !=
           std::string::npos ||
       gpu_info->gl_extensions.find("GL_APPLE_framebuffer_multisample") !=
@@ skipping 132 matching lines @@
   for (size_t ii = 0; ii < gpu_info->secondary_gpus.size(); ++ii) {
     if (active_vendor_id == gpu_info->secondary_gpus[ii].vendor_id) {
       gpu_info->secondary_gpus[ii].active = true;
       return;
     }
   }
 }
 
 }  // namespace gpu