Fix the Android implementation of SelectFile() SEGV when params is NULL.

ui/shell_dialogs/select_file_dialog_android.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 "select_file_dialog_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 44 matching lines @@
     ui::SelectFileDialog::Type type,
     const string16& title,
     const base::FilePath& default_path,
     const SelectFileDialog::FileTypeInfo* file_types,
     int file_type_index,
     const std::string& default_extension,
     gfx::NativeWindow owning_window,
     void* params) {
   JNIEnv* env = base::android::AttachCurrentThread();
 
-  std::vector<string16> accept_types =
-      *(reinterpret_cast<std::vector<string16>*>(params));
+  ScopedJavaLocalRef<jstring> capture_value;
+  std::vector<string16> accept_types;
+  if (params) {
+    accept_types = *(reinterpret_cast<std::vector<string16>*>(params));
 
-  // The last string in params is expected to be the string with capture value.
-  ScopedJavaLocalRef<jstring> capture_value =
-      base::android::ConvertUTF16ToJavaString(env,
+    // The last string in params is expected to be the string
+    // with capture value.
+    capture_value = base::android::ConvertUTF16ToJavaString(env,
           StringToLowerASCII(accept_types.back()));
-  base::android::CheckException(env);
-  accept_types.pop_back();
+    base::android::CheckException(env);
+    accept_types.pop_back();
+  } else {
+    capture_value = base::android::ConvertUTF8ToJavaString(env, "filesystem");
+  }
 
   // The rest params elements are expected to be accept_types.
   ScopedJavaLocalRef<jobjectArray> accept_types_java =
       base::android::ToJavaArrayOfStrings(env, accept_types);
 
   Java_SelectFileDialog_selectFile(env, java_object_.obj(),
                                    accept_types_java.obj(),
                                    capture_value.obj(),
                                    owning_window->GetJavaObject().obj());
   is_running_ = true;
@@ skipping 20 matching lines @@
   return false;
 }
 
 SelectFileDialog* CreateAndroidSelectFileDialog(
     SelectFileDialog::Listener* listener,
     SelectFilePolicy* policy) {
   return SelectFileDialogImpl::Create(listener, policy);
 }
 
 }  // namespace ui