More speedup of scrolling when many windowed plugins in a page. Scrolling is...

webkit/glue/plugins/webplugin_delegate_impl.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.
 
 #include "webkit/glue/plugins/webplugin_delegate_impl.h"
 
 #include <string>
 #include <vector>
 
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/stats_counters.h"
 #include "base/string_util.h"
 #include "webkit/default_plugin/plugin_impl.h"
 #include "webkit/glue/glue_util.h"
 #include "webkit/glue/webplugin.h"
+#include "webkit/glue/plugins/plugin_constants_win.h"
 #include "webkit/glue/plugins/plugin_instance.h"
 #include "webkit/glue/plugins/plugin_lib.h"
 #include "webkit/glue/plugins/plugin_list.h"
 #include "webkit/glue/plugins/plugin_stream_url.h"
 #include "webkit/glue/webkit_glue.h"
 
 static StatsCounter windowless_queue("Plugin.ThrottleQueue");
 
-static const wchar_t kNativeWindowClassName[] = L"NativeWindowClass";
 static const wchar_t kWebPluginDelegateProperty[] =
     L"WebPluginDelegateProperty";
 static const wchar_t kPluginNameAtomProperty[] = L"PluginNameAtom";
 static const wchar_t kDummyActivationWindowName[] = L"DummyWindowForActivation";
 static const wchar_t kPluginOrigProc[] = L"OriginalPtr";
 static const wchar_t kPluginFlashThrottle[] = L"FlashThrottle";
 
 // The fastest we are willing to process WM_USER+1 events for Flash.
 // Flash can easily exceed the limits of our CPU if we don't throttle it.
 // The throttle has been chosen by testing various delays and compromising
@@ skipping 750 matching lines @@
       delegate->quirks() & PLUGIN_QUIRK_DONT_CALL_WND_PROC_RECURSIVELY &&
       delegate->is_calling_wndproc) {
     // Real may go into a state where it recursively dispatches the same event
     // when subclassed.  See https://bugzilla.mozilla.org/show_bug.cgi?id=192914
     // We only do the recursive check for Real because it's possible and valid
     // for a plugin to synchronously dispatch a message to itself such that it
     // looks like it's in recursion.
     return TRUE;
   }
 
+  static UINT custom_msg = RegisterWindowMessage(kPaintMessageName);
+  if (message == custom_msg) {
+    // Get the invalid rect which is in screen coordinates and convert to
+    // window coordinates.
+    gfx::Rect invalid_rect;
+    invalid_rect.set_x(wparam >> 16);
+    invalid_rect.set_y(wparam & 0xFFFF);
+    invalid_rect.set_width(lparam >> 16);
+    invalid_rect.set_height(lparam & 0xFFFF);
+
+    RECT window_rect;
+    GetWindowRect(hwnd, &window_rect);
+    invalid_rect.Offset(-window_rect.left, -window_rect.top);
+
+    // The plugin window might have non-client area.   If we don't pass in
+    // RDW_FRAME then the children don't receive WM_NCPAINT messages while
+    // scrolling, which causes painting problems (http://b/issue?id=923945).
+    RedrawWindow(hwnd, &invalid_rect.ToRECT(), NULL,
+                 RDW_UPDATENOW | RDW_INVALIDATE | RDW_ALLCHILDREN | RDW_FRAME);
+    return FALSE;
+  }
+
   current_plugin_instance_ = delegate;
 
   switch (message) {
     case WM_NCDESTROY: {
       RemoveProp(hwnd, kWebPluginDelegateProperty);
       ATOM plugin_name_atom = reinterpret_cast  <ATOM>(
           RemoveProp(hwnd, kPluginNameAtomProperty));
       if (plugin_name_atom != 0)
         GlobalDeleteAtom(plugin_name_atom);
       ClearThrottleQueueForWindow(hwnd);
@@ skipping 324 matching lines @@
 
   // It is ok to pass NULL here to GetCursor as we are not looking for cursor
   // types defined by Webkit.
   HCURSOR previous_cursor =
       current_plugin_instance_->current_windowless_cursor_.GetCursor(NULL);
 
   current_plugin_instance_->current_windowless_cursor_.InitFromExternalCursor(
       cursor);
   return previous_cursor;
 }