Fix use after free in JavascriptAppModalDialogAndroid.

chrome/browser/ui/android/javascript_app_modal_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 "chrome/browser/ui/android/javascript_app_modal_dialog_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/utf_string_conversions.h"
 
@@ skipping 21 matching lines @@
 }
 
 JavascriptAppModalDialogAndroid::JavascriptAppModalDialogAndroid(
     JNIEnv* env,
     JavaScriptAppModalDialog* dialog,
     gfx::NativeWindow parent)
     : dialog_(dialog),
       parent_jobject_weak_ref_(env, parent->GetJavaObject().obj()) {
 }
 
-JavascriptAppModalDialogAndroid::~JavascriptAppModalDialogAndroid() {
-  JNIEnv* env = AttachCurrentThread();
-  // In case the dialog is still displaying, tell it to close itself.
-  // This can happen if you trigger a dialog but close the Tab before it's
-  // shown, and then accept the dialog.
-  if (!dialog_jobject_.is_null())
-    Java_JavascriptAppModalDialog_dismiss(env, dialog_jobject_.obj());
-}
-
 int JavascriptAppModalDialogAndroid::GetAppModalDialogButtons() const {
   NOTIMPLEMENTED();
   return 0;
 }
 
 void JavascriptAppModalDialogAndroid::ShowAppModalDialog() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   JNIEnv* env = AttachCurrentThread();
   // Keep a strong ref to the parent window while we make the call to java to
@@ skipping 95 matching lines @@
   JavascriptAppModalDialogAndroid* js_dialog =
       static_cast<JavascriptAppModalDialogAndroid*>(dialog->native_dialog());
   return js_dialog->GetDialogObject().obj();
 }
 
 // static
 bool JavascriptAppModalDialogAndroid::RegisterJavascriptAppModalDialog(
     JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
+
+JavascriptAppModalDialogAndroid::~JavascriptAppModalDialogAndroid() {
+  JNIEnv* env = AttachCurrentThread();
+  // In case the dialog is still displaying, tell it to close itself.
+  // This can happen if you trigger a dialog but close the Tab before it's
+  // shown, and then accept the dialog.
+  if (!dialog_jobject_.is_null())
+    Java_JavascriptAppModalDialog_dismiss(env, dialog_jobject_.obj());
+}