Use PathService in installer::GetModulePath().

chrome/installer/util/module_util_win.cc

 // Copyright (c) 2015 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 <windows.h>
-
 #include "chrome/installer/util/module_util_win.h"
 
+#include "base/base_paths.h"
 #include "base/file_version_info.h"
 #include "base/files/file.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/version.h"
 
 namespace installer {
 
 namespace {
 
-// Returns the directory in which the currently running executable resides.
-base::FilePath GetExecutableDir() {
-  base::char16 path[MAX_PATH];
-  ::GetModuleFileNameW(nullptr, path, MAX_PATH);
-  return base::FilePath(path).DirName();
-}
-
-// Returns the version in the current module's version resource or the empty
-// string if none found.
-base::string16 GetCurrentModuleVersion() {
+// Returns the version in the current executable's version resource.
+base::string16 GetCurrentExecutableVersion() {
   scoped_ptr<FileVersionInfo> file_version_info(
       CREATE_FILE_VERSION_INFO_FOR_CURRENT_MODULE());
-  if (file_version_info.get()) {
-    base::string16 version_string(file_version_info->file_version());
-    if (Version(base::UTF16ToASCII(version_string)).IsValid())
-      return version_string;
-  }
-  return base::string16();
+  DCHECK(file_version_info.get());
+  base::string16 version_string(file_version_info->file_version());
+  DCHECK(base::Version(base::UTF16ToASCII(version_string)).IsValid());
+  return version_string;
 }
 
 // Indicates whether a file can be opened using the same flags that
 // ::LoadLibrary() uses to open modules.
 bool ModuleCanBeRead(const base::FilePath file_path) {
   return base::File(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ)
       .IsValid();
 }
 
 }  // namespace
 
 base::FilePath GetModulePath(base::StringPiece16 module_name,
                              base::string16* version) {
   DCHECK(version);
 
-  base::FilePath module_dir = GetExecutableDir();
-  base::FilePath module = module_dir.Append(module_name);
-  if (ModuleCanBeRead(module))
-    return module;
+  base::FilePath exe_dir;
+  const bool has_path = base::PathService::Get(base::DIR_EXE, &exe_dir);
+  DCHECK(has_path);
 
-  base::string16 version_string(GetCurrentModuleVersion());
-  if (version_string.empty()) {
-    LOG(ERROR) << "No valid Chrome version found";
-    return base::FilePath();
-  }
-  *version = version_string;
-  return module_dir.Append(version_string).Append(module_name);
+  // Look for the module in the current executable's directory and return the
+  // path if it can be read. This is the expected location of modules for dev
+  // builds.
+  const base::FilePath module_path = exe_dir.Append(module_name);
+  if (ModuleCanBeRead(module_path))
+    return module_path;
+
+  // Othwerwise, return the path to the module in a versioned sub-directory of
+  // the current executable's directory. This is the expected location of
+  // modules for proper installs.
+  *version = GetCurrentExecutableVersion();
+  DCHECK(!version->empty());
+
+  return exe_dir.Append(*version).Append(module_name);
 }
 
 }  // namespace installer