Check for existence of taskbar pins dir in path provider.

This directory may not exist for a user. PathService's contract is that
it either returns an empty path or it returns the path to a dir that
exists, so it must enforce that.

BUG=1053446

Change-Id: I56a187039363f1b76306a3914e7dc73ad3c2737d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2096681Reviewed-by: Patrick Monette <pmonette@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749181}

base/base_paths_win.cc

@@ -9,9 +9,12 @@
 #include "base/base_paths.h"
 #include "base/environment.h"
 #include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/location.h"
 #include "base/path_service.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/win/current_module.h"
 #include "base/win/scoped_co_mem.h"
 #include "base/win/windows_version.h"
@@ -172,12 +175,19 @@ bool PathProviderWin(int key, FilePath* result) {
                 .Append(FILE_PATH_LITERAL("Internet Explorer"))
                 .Append(FILE_PATH_LITERAL("Quick Launch"));
       break;
-    case base::DIR_TASKBAR_PINS:
+    case base::DIR_TASKBAR_PINS: {
       if (!PathService::Get(base::DIR_USER_QUICK_LAUNCH, &cur))
         return false;
       cur = cur.Append(FILE_PATH_LITERAL("User Pinned"))
                 .Append(FILE_PATH_LITERAL("TaskBar"));
+      // Allow a blocking call here to check for existence of the directory. In
+      // practice, all uses of SHGetFolderPath in this function make a similar
+      // check, so this does not add new I/O that wasn't already happening.
+      ScopedAllowBlocking allow_blocking(FROM_HERE);
+      if (!DirectoryExists(cur))
+        return false;
       break;
+    }
     case base::DIR_IMPLICIT_APP_SHORTCUTS:
       if (!PathService::Get(base::DIR_USER_QUICK_LAUNCH, &cur))
         return false;

base/threading/thread_restrictions.h

@@ -303,12 +303,15 @@ class TaskTracker;
 
 class AdjustOOMScoreHelper;
 class FileDescriptorWatcher;
+class FilePath;
 class GetAppOutputScopedAllowBaseSyncPrimitives;
 class ScopedAllowThreadRecallForStackSamplingProfiler;
 class SimpleThread;
 class StackSamplingProfiler;
 class Thread;
 
+bool PathProviderWin(int, FilePath*);
+
 #if DCHECK_IS_ON()
 #define INLINE_IF_DCHECK_IS_OFF BASE_EXPORT
 #define EMPTY_BODY_IF_DCHECK_IS_OFF
@@ -376,6 +379,8 @@ class BASE_EXPORT ScopedAllowBlocking {
   friend class content::RenderProcessHostImpl;
   friend class weblayer::WebLayerPathProvider;
 
+  friend bool PathProviderWin(int, FilePath*);
+
   ScopedAllowBlocking(const Location& from_here = Location::Current());
   ~ScopedAllowBlocking();
 

chrome/browser/shell_integration_win.cc

@@ -735,20 +735,6 @@ void MigrateTaskbarPins(base::OnceClosure completion_callback) {
   // This needs to happen (e.g. so that the appid is fixed and the
   // run-time Chrome icon is merged with the taskbar shortcut), but it is not an
   // urgent task.
-  base::FilePath taskbar_path;
-  if (!base::PathService::Get(base::DIR_TASKBAR_PINS, &taskbar_path)) {
-    NOTREACHED();
-    return;
-  }
-
-  // Migrate any pinned shortcuts in ImplicitApps sub-directories.
-  base::FilePath implicit_apps_path;
-  if (!base::PathService::Get(base::DIR_IMPLICIT_APP_SHORTCUTS,
-                              &implicit_apps_path)) {
-    NOTREACHED();
-    return;
-  }
-
   // MigrateTaskbarPinsCallback just calls MigrateShortcutsInPathInternal
   // several times with different parameters.  Each call may or may not load
   // DLL's. Since the callback may take the loader lock several times, and this
@@ -761,10 +747,16 @@ void MigrateTaskbarPins(base::OnceClosure completion_callback) {
   base::ThreadPool::CreateCOMSTATaskRunner(
       {base::MayBlock(), base::TaskPriority::BEST_EFFORT,
        base::ThreadPolicy::MUST_USE_FOREGROUND})
-      ->PostTaskAndReply(FROM_HERE,
-                         base::BindOnce(&MigrateTaskbarPinsCallback,
-                                        taskbar_path, implicit_apps_path),
-                         std::move(completion_callback));
+      ->PostTaskAndReply(
+          FROM_HERE, base::BindOnce([]() {
+            base::FilePath taskbar_path;
+            base::FilePath implicit_apps_path;
+            base::PathService::Get(base::DIR_TASKBAR_PINS, &taskbar_path);
+            base::PathService::Get(base::DIR_IMPLICIT_APP_SHORTCUTS,
+                                   &implicit_apps_path);
+            MigrateTaskbarPinsCallback(taskbar_path, implicit_apps_path);
+          }),
+          std::move(completion_callback));
 }
 
 void MigrateTaskbarPinsCallback(const base::FilePath& taskbar_path,
@@ -775,8 +767,12 @@ void MigrateTaskbarPinsCallback(const base::FilePath& taskbar_path,
     return;
   base::FilePath chrome_proxy_path(web_app::GetChromeProxyPath());
 
-  MigrateChromeAndChromeProxyShortcuts(chrome_exe, chrome_proxy_path,
-                                       taskbar_path);
+  if (!taskbar_path.empty()) {
+    MigrateChromeAndChromeProxyShortcuts(chrome_exe, chrome_proxy_path,
+                                         taskbar_path);
+  }
+  if (implicit_apps_path.empty())
+    return;
   base::FileEnumerator directory_enum(implicit_apps_path, /*recursive=*/false,
                                       base::FileEnumerator::DIRECTORIES);
   for (base::FilePath implicit_app_sub_directory = directory_enum.Next();

chrome/installer/util/shell_util.cc

@@ -1603,8 +1603,8 @@ bool ShellUtil::GetShortcutPath(ShortcutLocation location,
       folder_to_append = InstallUtil::GetChromeAppsShortcutDirName();
       break;
     case SHORTCUT_LOCATION_TASKBAR_PINS:
-      dir_key = base::DIR_TASKBAR_PINS;
-      break;
+      // This directory isn't guaranteed to exist.
+      return base::PathService::Get(base::DIR_TASKBAR_PINS, path);
     case SHORTCUT_LOCATION_APP_SHORTCUTS:
       // TODO(huangs): Move GetAppShortcutsFolder() logic into base_paths_win.
       return GetAppShortcutsFolder(level, path);

chrome/services/util_win/util_win_impl.cc

@@ -188,21 +188,24 @@ bool IsPinnedToTaskbarHelper::DirectoryContainsPinnedShortcutForProgram(
 
 bool IsPinnedToTaskbarHelper::GetResult() {
   base::FilePath current_exe;
-  base::PathService::Get(base::FILE_EXE, &current_exe);
+  if (!base::PathService::Get(base::FILE_EXE, &current_exe))
+    return false;
 
   InstallUtil::ProgramCompare current_exe_compare(current_exe);
   // Look into the "Quick Launch\User Pinned\TaskBar" folder.
   base::FilePath taskbar_pins_dir;
-  base::PathService::Get(base::DIR_TASKBAR_PINS, &taskbar_pins_dir);
-  if (DirectoryContainsPinnedShortcutForProgram(taskbar_pins_dir,
+  if (base::PathService::Get(base::DIR_TASKBAR_PINS, &taskbar_pins_dir) &&
+      DirectoryContainsPinnedShortcutForProgram(taskbar_pins_dir,
                                                 current_exe_compare)) {
     return true;
   }
 
   // Check all folders in ImplicitAppShortcuts.
   base::FilePath implicit_app_shortcuts_dir;
-  base::PathService::Get(base::DIR_IMPLICIT_APP_SHORTCUTS,
-                         &implicit_app_shortcuts_dir);
+  if (!base::PathService::Get(base::DIR_IMPLICIT_APP_SHORTCUTS,
+                              &implicit_app_shortcuts_dir)) {
+    return false;
+  }
   base::FileEnumerator directory_enum(implicit_app_shortcuts_dir, false,
                                       base::FileEnumerator::DIRECTORIES);
   for (base::FilePath directory = directory_enum.Next(); !directory.empty();