Support ozone=1 compositor_unittests with OSMesa

ui/gl/gl_implementation_linux.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.
+
+#include "ui/gl/gl_implementation_linux.h"
+
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/native_library.h"
+#include "base/path_service.h"
+#include "ui/gl/gl_bindings.h"
+#include "ui/gl/gl_gl_api_implementation.h"
+#include "ui/gl/gl_implementation.h"
+#include "ui/gl/gl_osmesa_api_implementation.h"
+
+namespace gfx {
+
+// Load a library, printing an error message on failure.
+base::NativeLibrary LoadLibrary(const base::FilePath& filename) {
+  std::string error;
+  base::NativeLibrary library = base::LoadNativeLibrary(filename,
+                                                        &error);
+  if (!library) {
+    DVLOG(1) << "Failed to load " << filename.MaybeAsASCII() << ": " << error;
+    return NULL;
+  }
+  return library;
+}
+
+base::NativeLibrary LoadLibrary(const char* filename) {
+  return LoadLibrary(base::FilePath(filename));
+}
+
+bool InitializeGLBindingsOSMesaGL() {
+      base::FilePath module_path;
+      if (!PathService::Get(base::DIR_MODULE, &module_path)) {
+        LOG(ERROR) << "PathService::Get failed.";
+        return false;
+      }
+
+      base::NativeLibrary library = LoadLibrary(
+          module_path.Append("libosmesa.so"));
+      if (!library)
+        return false;
+
+      GLGetProcAddressProc get_proc_address =
+          reinterpret_cast<GLGetProcAddressProc>(
+              base::GetFunctionPointerFromNativeLibrary(
+                  library, "OSMesaGetProcAddress"));
+      if (!get_proc_address) {
+        LOG(ERROR) << "OSMesaGetProcAddress not found.";
+        base::UnloadNativeLibrary(library);
+        return false;
+      }
+
+      SetGLGetProcAddressProc(get_proc_address);
+      AddGLNativeLibrary(library);
+      SetGLImplementation(kGLImplementationOSMesaGL);
+
+      InitializeGLBindingsGL();
+      InitializeGLBindingsOSMESA();
+    return true;
+}
+
+}  // namespace gfx