Windows: Add an "Open in Adobe Reader" menu item for PDF files in the download shelf.

content/public/common/registry_utils_win.cc

+// Copyright 2014 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 "content/public/common/registry_utils_win.h"
+
+#include "base/files/file_path.h"
+#include "base/win/registry.h"
+#include "base/win/windows_version.h"
+
+namespace content {
+
+const base::char16 kRegistryAppsKey[] =
+    L"Software\\Microsoft\\Windows\\CurrentVersion\\App Paths";
+const base::char16 kRegistryPath[] = L"Path";
+
+const base::char16 kRegistryAcrobat[] = L"Acrobat.exe";
+const base::char16 kRegistryAcrobatReader[] = L"AcroRd32.exe";
+
+bool GetInstalledPath(const base::char16* app, base::FilePath* out) {
+  base::string16 reg_path(kRegistryAppsKey);
+  reg_path.append(L"\\");
+  reg_path.append(app);
+
+  base::win::RegKey hkcu_key(HKEY_CURRENT_USER, reg_path.c_str(), KEY_READ);
+  base::string16 path;
+  // As of Win7 AppPaths can also be registered in HKCU: http://goo.gl/UgFOf.
+  if (base::win::GetVersion() >= base::win::VERSION_WIN7 &&
+      hkcu_key.ReadValue(kRegistryPath, &path) == ERROR_SUCCESS) {
+    *out = base::FilePath(path);
+    return true;
+  } else {
+    base::win::RegKey hklm_key(HKEY_LOCAL_MACHINE, reg_path.c_str(), KEY_READ);
+    if (hklm_key.ReadValue(kRegistryPath, &path) == ERROR_SUCCESS) {
+      *out = base::FilePath(path);
+      return true;
+    }
+  }
+
+  return false;
+}
+
+}  // namespace content