Enforce the 'requirements' field in manifests.

chrome/browser/extensions/requirements_checker.cc

Index: chrome/browser/extensions/requirements_checker.cc
diff --git a/chrome/browser/extensions/requirements_checker.cc b/chrome/browser/extensions/requirements_checker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..516f5b0e083ba2d4c2533443ee47429f00cddbde
--- /dev/null
+++ b/chrome/browser/extensions/requirements_checker.cc
@@ -0,0 +1,98 @@
+// 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 "chrome/browser/extensions/requirements_checker.h"
+
+#include "base/bind.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/browser/gpu_feature_checker.h"
+#include "chrome/common/extensions/extension_manifest_constants.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/manifest.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/common/gpu_feature_type.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace extensions {
+
+RequirementsChecker::RequirementsChecker()
+    : pending_requirement_checks_(0) {
+}
+
+RequirementsChecker::~RequirementsChecker() {
+}
+
+void RequirementsChecker::Check(scoped_refptr<const Extension> extension,
+    base::Callback<void(std::vector<std::string> errors)> callback) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  callback_ = callback;
+  const Extension::Requirements& requirements = extension->requirements();
+
+  if (requirements.npapi) {
+#if defined(OS_CHROMEOS)
+    errors_.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
+#endif  // defined(OS_CHROMEOS)
+  }
+
+  if (requirements.webgl) {
+    ++pending_requirement_checks_;
+    webgl_checker_ = new GPUFeatureChecker(
+      content::GPU_FEATURE_TYPE_WEBGL,
+      base::Bind(&RequirementsChecker::SetWebGLAvailability,
+                 AsWeakPtr()));
+  }
+
+  if (requirements.css3d) {
+    ++pending_requirement_checks_;
+    css3d_checker_ = new GPUFeatureChecker(
+      content::GPU_FEATURE_TYPE_ACCELERATED_COMPOSITING,
+      base::Bind(&RequirementsChecker::SetCSS3DAvailability,
+                 AsWeakPtr()));
+  }
+
+  if (pending_requirement_checks_ == 0) {
+    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+                                     base::Bind(callback_, errors_));
+    // Reset the callback so any ref-counted bound parameters will get released.
+    callback_.Reset();
+    return;
+  }
+  // Running the GPU checkers down here removes any race condition that arises
+  // from the use of pending_requirement_checks_.
+  if (webgl_checker_.get())
+    webgl_checker_->CheckGPUFeatureAvailability();
+  if (css3d_checker_.get())
+    css3d_checker_->CheckGPUFeatureAvailability();
+}
+
+void RequirementsChecker::SetWebGLAvailability(bool available) {
+  if (!available) {
+    errors_.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_WEBGL_NOT_SUPPORTED));
+  }
+  MaybeRunCallback();
+}
+
+void RequirementsChecker::SetCSS3DAvailability(bool available) {
+  if (!available) {
+    errors_.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_CSS3D_NOT_SUPPORTED));
+  }
+  MaybeRunCallback();
+}
+
+void RequirementsChecker::MaybeRunCallback() {
+  if (--pending_requirement_checks_ == 0) {
+    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+                                     base::Bind(callback_, errors_));
+    // Reset the callback so any ref-counted bound parameters will get released.
+    callback_.Reset();
+    errors_.clear();
+  }
+}
+
+}  // namespace extensions