Adds a TransportDIB::Id value that is explicitly invalid and use it when compositing

chrome/renderer/render_widget.cc

 // Copyright (c) 2010 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 "chrome/renderer/render_widget.h"
 
 #include "app/surface/transport_dib.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 558 matching lines @@
     return;
 
   // OK, save the pending update to a local since painting may cause more
   // invalidation.  Some WebCore rendering objects only layout when painted.
   PaintAggregator::PendingUpdate update;
   paint_aggregator_.PopPendingUpdate(&update);
 
   gfx::Rect scroll_damage = update.GetScrollDamage();
   gfx::Rect bounds = update.GetPaintBounds().Union(scroll_damage);
 
+  // Compositing the page may disable accelerated compositing.
+  bool accelerated_compositing_was_active = is_accelerated_compositing_active_;
+
   // A plugin may be able to do an optimized paint. First check this, in which
   // case we can skip all of the bitmap generation and regular paint code.
   // This optimization allows PPAPI plugins that declare themselves on top of
   // the page (like a traditional windowed plugin) to be able to animate (think
   // movie playing) without repeatedly re-painting the page underneath, or
   // copying the plugin backing store (since we can send the plugin's backing
   // store directly to the browser).
   //
   // This optimization only works when the entire invalid region is contained
   // within the plugin. There is a related optimization in PaintRect for the
   // case where there may be multiple invalid regions.
-  TransportDIB::Id dib_id = TransportDIB::Id();
+  TransportDIB::Id dib_id = TransportDIB::InvalidId();
   TransportDIB* dib = NULL;
   std::vector<gfx::Rect> copy_rects;
   gfx::Rect optimized_copy_rect, optimized_copy_location;
   if (update.scroll_rect.IsEmpty() &&
       !is_accelerated_compositing_active_ &&
       GetBitmapForOptimizedPluginPaint(bounds, &dib, &optimized_copy_location,
                                        &optimized_copy_rect)) {
     // Only update the part of the plugin that actually changed.
     optimized_copy_rect = optimized_copy_rect.Intersect(bounds);
     bounds = optimized_copy_location;
@@ skipping 31 matching lines @@
     // Begin painting.
     webwidget_->composite(false);
   }
 
   // sending an ack to browser process that the paint is complete...
   ViewHostMsg_UpdateRect_Params params;
   params.bitmap = dib_id;
   params.bitmap_rect = bounds;
   params.dx = update.scroll_delta.x();
   params.dy = update.scroll_delta.y();
-  if (is_accelerated_compositing_active_) {
+  if (accelerated_compositing_was_active) {
     // If painting is done via the gpu process then we clear out all damage
     // rects to save the browser process from doing unecessary work.
     params.scroll_rect = gfx::Rect();
     params.copy_rects.clear();
   } else {
     params.scroll_rect = update.scroll_rect;
     params.copy_rects.swap(copy_rects);  // TODO(darin): clip to bounds?
   }
   params.view_size = size_;
   params.resizer_rect = resizer_rect_;
@@ skipping 449 matching lines @@
 
 void RenderWidget::CleanupWindowInPluginMoves(gfx::PluginWindowHandle window) {
   for (WebPluginGeometryVector::iterator i = plugin_window_moves_.begin();
        i != plugin_window_moves_.end(); ++i) {
     if (i->window == window) {
       plugin_window_moves_.erase(i);
       break;
     }
   }
 }