Use PreloadCheckGroup in ExtensionInstallChecker. Make RequirementsChecker a PreloadCheck.

extensions/browser/requirements_checker.cc

+// Copyright 2017 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 "extensions/browser/requirements_checker.h"
+
+// TODO
+#include "base/bind.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/strings/string_util.h"
+#include "build/build_config.h"
+#include "content/public/browser/gpu_feature_checker.h"
+#include "content/public/browser/browser_thread.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/manifest.h"
+#include "extensions/common/manifest_handlers/requirements_info.h"
+#include "extensions/strings/grit/extensions_strings.h"
+#include "gpu/config/gpu_feature_type.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace extensions {
+
+RequirementsChecker::RequirementsChecker(const Extension* extension)
+    : PreloadCheck(extension), weak_ptr_factory_(this) {}
+
+RequirementsChecker::~RequirementsChecker() {}
+
+void RequirementsChecker::Start(ResultCallback callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  const RequirementsInfo& requirements =
+      RequirementsInfo::GetRequirements(extension());
+
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+  if (requirements.npapi)
+    errors_.insert(NPAPI_NOT_SUPPORTED);
+#endif
+
+#if !defined(USE_AURA)
+  if (requirements.window_shape)
+    errors_.insert(WINDOW_SHAPE_NOT_SUPPORTED);
+#endif
+
+  if (requirements.webgl) {
+    webgl_checker_ = content::GpuFeatureChecker::Create(
+        gpu::GPU_FEATURE_TYPE_WEBGL,
+        base::Bind(&RequirementsChecker::OnGetWebGLAvailability,
+                   weak_ptr_factory_.GetWeakPtr()));
+    webgl_checker_->CheckGpuFeatureAvailability();
+    callback_ = std::move(callback);
+  } else {
+    std::move(callback).Run(errors_);
+  }
+}
+
+base::string16 RequirementsChecker::GetErrorMessage() const {
+  // Join the error messages into one string.
+  std::vector<std::string> messages;
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+  if (errors_.count(NPAPI_NOT_SUPPORTED)) {
+    messages.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
+  }
+#endif
+  if (errors_.count(WEBGL_NOT_SUPPORTED)) {
+    messages.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_WEBGL_NOT_SUPPORTED));
+  }
+#if !defined(USE_AURA)
+  if (errors_.count(WINDOW_SHAPE_NOT_SUPPORTED)) {
+    messages.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_WINDOW_SHAPE_NOT_SUPPORTED));
+  }
+#endif
+
+  return base::UTF8ToUTF16(base::JoinString(messages, " "));
+}
+
+void RequirementsChecker::OnGetWebGLAvailability(bool available) {
+  if (!available)
+    errors_.insert(WEBGL_NOT_SUPPORTED);
+  std::move(callback_).Run(errors_);
+}
+
+}  // namespace extensions