Make sandboxed Flash work under UIPI

webkit/plugins/npapi/webplugin_delegate_impl_win.cc

Index: webkit/plugins/npapi/webplugin_delegate_impl_win.cc
===================================================================
--- webkit/plugins/npapi/webplugin_delegate_impl_win.cc	(revision 87939)
+++ webkit/plugins/npapi/webplugin_delegate_impl_win.cc	(working copy)
@@ -271,9 +271,11 @@
       last_message_(0),
       is_calling_wndproc(false),
       dummy_window_for_activation_(NULL),
+      parent_proxy_window_(NULL),
       handle_event_message_filter_hook_(NULL),
       handle_event_pump_messages_event_(NULL),
       user_gesture_message_posted_(false),
+      is_builtin_flash_(false),
 #pragma warning(suppress: 4355)  // can use this
       user_gesture_msg_factory_(this),
       handle_event_depth_(0),
@@ -289,7 +291,9 @@
   std::wstring filename =
       StringToLowerASCII(plugin_info.path.BaseName().value());
 
-  if (instance_->mime_type() == "application/x-shockwave-flash" ||
+  is_builtin_flash_ = filename == kBuiltinFlashPlugin;
+  if (is_builtin_flash_ ||
+      instance_->mime_type() == "application/x-shockwave-flash" ||
       filename == kFlashPlugin) {
     // Flash only requests windowless plugins if we return a Mozilla user
     // agent.
@@ -354,7 +358,11 @@
 
 WebPluginDelegateImpl::~WebPluginDelegateImpl() {
   if (::IsWindow(dummy_window_for_activation_)) {
-    ::DestroyWindow(dummy_window_for_activation_);
+    // Sandboxed Flash stacks two dummy windows to prevent UIPI failures
+    if (::IsWindow(parent_proxy_window_))
+      ::DestroyWindow(parent_proxy_window_);
+    else
+      ::DestroyWindow(dummy_window_for_activation_);
   }
 
   DestroyInstance();
@@ -492,14 +500,16 @@
       0,
       0,
       0,

[ananta, 2011/06/07 00:40:08]

Please add some comments here which explain what we are trying to achieve with
the SetParent magic.

[cpu_(ooo_6.6-7.5), 2011/06/07 01:03:36]

what Ananta said.

On 2011/06/07 00:40:08, ananta wrote:

-      parent_,
+      is_builtin_flash_ ? NULL : parent_,
       0,
       GetModuleHandle(NULL),
       0);
   if (windowed_handle_ == 0)
     return false;
 
-  if (IsWindow(parent_)) {
+  if (is_builtin_flash_) {
+    plugin_->ReparentPluginWindow(windowed_handle_, parent_);
+  } else if (IsWindow(parent_)) {
     // This is a tricky workaround for Issue 2673 in chromium "Flash: IME not
     // available". To use IMEs in this window, we have to make Windows attach
     // IMEs to this window (i.e. load IME DLLs, attach them to this process,
@@ -705,6 +715,30 @@
 
 bool WebPluginDelegateImpl::CreateDummyWindowForActivation() {
   DCHECK(!dummy_window_for_activation_);
+
+  // Built-in Flash runs with UIPI, but in windowless mode Flash sometimes
+  // tries to attach windows to the parent (which fails under UIPI). To make
+  // it work we add an extra dummy parent in the low-integrity process.
+  if (is_builtin_flash_) {
+    parent_proxy_window_ = CreateWindowEx(
+      0,
+      L"Static",
+      kDummyActivationWindowName,
+      WS_POPUP,
+      0,
+      0,
+      0,
+      0,
+      0,
+      0,
+      GetModuleHandle(NULL),
+      0);
+
+    if (parent_proxy_window_ == 0)
+      return false;
+    plugin_->ReparentPluginWindow(parent_proxy_window_, parent_);
+  }
+
   dummy_window_for_activation_ = CreateWindowEx(
     0,
     L"Static",
@@ -714,7 +748,7 @@
     0,
     0,
     0,
-    parent_,
+    parent_proxy_window_ ? parent_proxy_window_ : parent_,
     0,
     GetModuleHandle(NULL),
     0);