We need to set the clipping region of the HDC passed in to a windowless flash...

webkit/glue/plugins/test/plugin_windowless_test.cc

+// Copyright (c) 2006-2008 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.
+
+#define STRSAFE_NO_DEPRECATE
+#include "webkit/glue/plugins/test/plugin_windowless_test.h"
+#include "webkit/glue/plugins/test/plugin_client.h"
+
+namespace NPAPIClient {
+
+WindowlessPluginTest::WindowlessPluginTest(
+    NPP id, NPNetscapeFuncs *host_functions, const std::string& test_name)
+  : PluginTest(id, host_functions),
+    test_name_(test_name) {
+}
+
+int16 WindowlessPluginTest::HandleEvent(void* event) {
+
+  NPNetscapeFuncs* browser = NPAPIClient::PluginClient::HostFunctions();
+
+  NPBool supports_windowless = 0;
+  NPError result = browser->getvalue(id(), NPNVSupportsWindowless,
+                                     &supports_windowless);
+  if ((result != NPERR_NO_ERROR) || (supports_windowless != TRUE)) {
+    SetError("Failed to read NPNVSupportsWindowless value");
+    SignalTestCompleted();
+    return PluginTest::HandleEvent(event);
+  }
+
+  NPEvent* np_event = reinterpret_cast<NPEvent*>(event);
+  if (WM_PAINT == np_event->event &&
+      base::strcasecmp(test_name_.c_str(),
+                       "execute_script_delete_in_paint") == 0) {
+    HDC paint_dc = reinterpret_cast<HDC>(np_event->wParam);
+    if (paint_dc == NULL) {
+      SetError("Invalid Window DC passed to HandleEvent for WM_PAINT");
+      SignalTestCompleted();
+      return NPERR_GENERIC_ERROR;
+    }
+
+    HRGN clipping_region = CreateRectRgn(0, 0, 0, 0);
+    if (!GetClipRgn(paint_dc, clipping_region)) {
+      SetError("No clipping region set in window DC");
+      DeleteObject(clipping_region);
+      SignalTestCompleted();
+      return NPERR_GENERIC_ERROR;
+    }
+
+    DeleteObject(clipping_region);
+
+    NPUTF8* urlString = "javascript:DeletePluginWithinScript()";
+    NPUTF8* targetString = NULL;
+    browser->geturl(id(), urlString, targetString);
+    SignalTestCompleted();
+  } else if (WM_MOUSEMOVE == np_event->event &&
+             base::strcasecmp(test_name_.c_str(),
+                              "execute_script_delete_in_mouse_move") == 0) {
+    std::string script = "javascript:DeletePluginWithinScript()";
+    NPString script_string;
+    script_string.UTF8Characters = script.c_str();
+    script_string.UTF8Length =
+        static_cast<unsigned int>(script.length());
+
+    NPObject *window_obj = NULL;
+    browser->getvalue(id(), NPNVWindowNPObject, &window_obj);
+    NPVariant result_var;
+    NPError result = browser->evaluate(id(), window_obj,
+                                       &script_string, &result_var);
+    SignalTestCompleted();
+  }
+  // If this test failed, then we'd have crashed by now.
+  return PluginTest::HandleEvent(event);
+}
+
+} // namespace NPAPIClient