Show download error message if sdcard is not available

chrome/browser/download/download_path_reservation_tracker.cc

 // 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/download/download_path_reservation_tracker.h"
 
 #include <stddef.h>
 
 #include <map>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/path_service.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/third_party/icu/icu_utf.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_paths.h"
+#include "chrome/common/features.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_item.h"
 
 using content::BrowserThread;
 using content::DownloadItem;
 
 namespace {
 
 typedef DownloadItem* ReservationKey;
 typedef std::map<ReservationKey, base::FilePath> ReservationMap;
@@ skipping 161 matching lines @@
       (create_directory ||
        (!default_download_path.empty() &&
         (default_download_path == target_dir)))) {
     base::CreateDirectory(target_dir);
   }
 
   // Check writability of the suggested path. If we can't write to it, default
   // to the user's "My Documents" directory. We'll prompt them in this case.
   if (!base::PathIsWritable(target_dir)) {
     DVLOG(1) << "Unable to write to directory \"" << target_dir.value() << "\"";
+#if BUILDFLAG(ANDROID_JAVA_UI)
+    // On Android, DIR_USER_DOCUMENTS is in reality a subdirectory
+    // of DIR_ANDROID_APP_DATA which isn't accessible by other apps.
+    reserved_path->clear();
+    (*g_reservation_map)[key] = *reserved_path;
+    return false;
+#else
     is_path_writeable = false;
     PathService::Get(chrome::DIR_USER_DOCUMENTS, &target_dir);
     target_path = target_dir.Append(filename);
+#endif  // BUILDFLAG(ANDROID_JAVA_UI)
   }
 
   if (is_path_writeable) {
     // Check the limit of file name length if it could be obtained. When the
     // suggested name exceeds the limit, truncate or prompt the user.
     int max_length = base::GetMaximumPathComponentLength(target_dir);
     if (max_length != -1) {
       int limit = max_length - kIntermediateNameSuffixLength;
       if (limit <= 0 || !TruncateFileName(&target_path, limit))
         name_too_long = true;
@@ skipping 171 matching lines @@
       base::Bind(&RunGetReservedPathCallback,
                  callback,
                  base::Owned(reserved_path)));
 }
 
 // static
 bool DownloadPathReservationTracker::IsPathInUseForTesting(
     const base::FilePath& path) {
   return IsPathInUse(path);
 }