From 96e116de9e2fb9e65b5acf82a1a6ccf2a0c7d6de Mon Sep 17 00:00:00 2001
From: Marshall Greenblatt <magreenblatt@gmail.com>
Date: Fri, 31 Jul 2015 14:45:31 -0400
Subject: [PATCH] Windows: Fix multiple handling of WM_MOUSEWHEEL messages
 (issue #1481)

---
 patch/patch.cfg                               |  6 ++++++
 patch/patches/hwnd_message_handler_1481.patch | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 patch/patches/hwnd_message_handler_1481.patch

diff --git a/patch/patch.cfg b/patch/patch.cfg
index e0c3af032..49ab96d4b 100644
--- a/patch/patch.cfg
+++ b/patch/patch.cfg
@@ -176,4 +176,10 @@ patches = [
     'name': 'process_title_1639',
     'path': '../content/common/',
   },
+  {
+    # Fix multiple handling of WM_MOUSEWHEEL messages on Windows.
+    # https://bitbucket.org/chromiumembedded/cef/issues/1481
+    'name': 'hwnd_message_handler_1481',
+    'path': '../ui/views/win/',
+  },
 ]
diff --git a/patch/patches/hwnd_message_handler_1481.patch b/patch/patches/hwnd_message_handler_1481.patch
new file mode 100644
index 000000000..ed7096d86
--- /dev/null
+++ b/patch/patches/hwnd_message_handler_1481.patch
@@ -0,0 +1,19 @@
+diff --git hwnd_message_handler.cc hwnd_message_handler.cc
+index bd2072b..c3fd2ea 100644
+--- hwnd_message_handler.cc
++++ hwnd_message_handler.cc
+@@ -2649,8 +2649,12 @@ LRESULT HWNDMessageHandler::HandleMouseEventInternal(UINT message,
+             "440919 HWNDMessageHandler::HandleMouseEventInternal6"));
+ 
+     // Reroute the mouse wheel to the window under the pointer if applicable.
+-    return (ui::RerouteMouseWheel(hwnd(), w_param, l_param) ||
+-            delegate_->HandleMouseEvent(ui::MouseWheelEvent(msg))) ? 0 : 1;
++    if (ui::RerouteMouseWheel(hwnd(), w_param, l_param) ||
++        delegate_->HandleMouseEvent(ui::MouseWheelEvent(msg))) {
++      SetMsgHandled(TRUE);
++      return 0;
++    }
++    return 1;
+   }
+ 
+   // TODO(vadimt): Remove ScopedTracker below once crbug.com/440919 is fixed.