Fire wxEVT_WEBVIEW_NAVIGATING when redirecting

When using IE wxWebView backend, this event wasn't generated as expected
when the client was redirected.

Fix this by using DOCHOSTUIFLAG_ENABLE_REDIRECT_NOTIFICATION flag.

Closes https://github.com/wxWidgets/wxWidgets/pull/893

docs/changes.txt

@@ -135,6 +135,7 @@ wxMSW:
 - Implement wxFontDialog::SetTitle() (Vitaly Stakhovsky).
 - Fix build in ANSI (non-Unicode) mode.
 - Improve wxNotebook themed background drawing (Arrigo Marchiori).
+- Send wxEVT_WEBVIEW_NAVIGATING when redirecting (Josue Andrade Gomes).
 
 wxOSX:
 

include/wx/msw/webview_missing.h

@@ -165,7 +165,8 @@ typedef enum _tagwxDOCHOSTUIFLAG
     DOCHOSTUIFLAG_NO3DOUTERBORDER = 0x200000,
     DOCHOSTUIFLAG_DISABLE_EDIT_NS_FIXUP = 0x400000,
     DOCHOSTUIFLAG_LOCAL_MACHINE_ACCESS_CHECK = 0x800000,
-    DOCHOSTUIFLAG_DISABLE_UNTRUSTEDPROTOCOL = 0x1000000
+    DOCHOSTUIFLAG_DISABLE_UNTRUSTEDPROTOCOL = 0x1000000,
+    DOCHOSTUIFLAG_ENABLE_REDIRECT_NOTIFICATION = 0x4000000
 } DOCHOSTUIFLAG;
 
 typedef struct _tagwxDOCHOSTUIINFO

src/msw/webview_ie.cpp

@@ -1640,8 +1640,12 @@ HRESULT wxSTDCALL DocHostUIHandler::ShowContextMenu(DWORD dwID, POINT *ppt,
 
 HRESULT wxSTDCALL DocHostUIHandler::GetHostInfo(DOCHOSTUIINFO *pInfo)
 {
-    //don't show 3d border and enable themes.
-    pInfo->dwFlags = pInfo->dwFlags | DOCHOSTUIFLAG_NO3DBORDER | DOCHOSTUIFLAG_THEME;
+    // Don't show 3d border and enable themes and also enable sending redirect
+    // notifications as otherwise we wouldn't get wxEVT_WEBVIEW_NAVIGATING when
+    // redirected.
+    pInfo->dwFlags |= DOCHOSTUIFLAG_NO3DBORDER |
+                      DOCHOSTUIFLAG_THEME |
+                      DOCHOSTUIFLAG_ENABLE_REDIRECT_NOTIFICATION;
     return S_OK;
 }