From 584bd26331ff4703bd95e490d5a7259474250d3c Mon Sep 17 00:00:00 2001
From: Marshall Greenblatt <magreenblatt@gmail.com>
Date: Tue, 29 May 2012 18:06:22 +0000
Subject: [PATCH] Windows: Allow the JS dialog message hook to be shared across
 multiple browser windows (issue #605).

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@654 5089003a-bbd8-11dd-ad1f-f1f9622dbc98
---
 libcef/browser/javascript_dialog.h      |  1 +
 libcef/browser/javascript_dialog_win.cc | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/libcef/browser/javascript_dialog.h b/libcef/browser/javascript_dialog.h
index bb6825468..14a598689 100644
--- a/libcef/browser/javascript_dialog.h
+++ b/libcef/browser/javascript_dialog.h
@@ -58,6 +58,7 @@ class CefJavaScriptDialog {
   static bool UninstallMessageHook();
   static LRESULT CALLBACK GetMsgProc(int code, WPARAM wparam, LPARAM lparam);
   static HHOOK msg_hook_;
+  static int msg_hook_user_count_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(CefJavaScriptDialog);
diff --git a/libcef/browser/javascript_dialog_win.cc b/libcef/browser/javascript_dialog_win.cc
index 3e6cf1edf..d24422203 100644
--- a/libcef/browser/javascript_dialog_win.cc
+++ b/libcef/browser/javascript_dialog_win.cc
@@ -16,6 +16,7 @@
 class CefJavaScriptDialog;
 
 HHOOK CefJavaScriptDialog::msg_hook_ = NULL;
+int CefJavaScriptDialog::msg_hook_user_count_ = 0;
 
 INT_PTR CALLBACK CefJavaScriptDialog::DialogProc(HWND dialog, UINT message,
                                                  WPARAM wparam,
@@ -192,8 +193,12 @@ LRESULT CALLBACK CefJavaScriptDialog::GetMsgProc(int code, WPARAM wparam,
 
 // static
 bool CefJavaScriptDialog::InstallMessageHook() {
+  msg_hook_user_count_++;
+
   // Make sure we only call this once.
-  DCHECK(msg_hook_ == NULL);
+  if (msg_hook_ != NULL)
+    return true;
+
   msg_hook_ = ::SetWindowsHookEx(WH_GETMESSAGE,
                                  &CefJavaScriptDialog::GetMsgProc,
                                  NULL,
@@ -204,6 +209,12 @@ bool CefJavaScriptDialog::InstallMessageHook() {
 
 // static
 bool CefJavaScriptDialog::UninstallMessageHook() {
+  msg_hook_user_count_--;
+  DCHECK_GE(msg_hook_user_count_, 0);
+
+  if (msg_hook_user_count_ > 0)
+    return true;
+
   DCHECK(msg_hook_ != NULL);
   BOOL result = ::UnhookWindowsHookEx(msg_hook_);
   DCHECK(result);