Fix invalidates from off-screen plugins on the Mac.

chrome/plugin/webplugin_proxy.cc

 // Copyright (c) 2009 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/plugin/webplugin_proxy.h"
 
 #include "build/build_config.h"
 
 #include "app/gfx/canvas.h"
 #if defined(OS_WIN)
@@ skipping 111 matching lines @@
 }
 
 void WebPluginProxy::Invalidate() {
   gfx::Rect rect(0, 0,
                  delegate_->GetRect().width(),
                  delegate_->GetRect().height());
   InvalidateRect(rect);
 }
 
 void WebPluginProxy::InvalidateRect(const gfx::Rect& rect) {
-  damaged_rect_ = damaged_rect_.Union(rect);
+#if defined(OS_MACOSX)
+  // Some plugins will send invalidates larger than their own rect when
+  // offscreen, so constrain invalidates to the plugin rect.
+  gfx::Rect plugin_rect = delegate_->GetRect();
+  plugin_rect.set_origin(gfx::Point(0, 0));
+  const gfx::Rect invalidate_rect(rect.Intersect(plugin_rect));
+#else
+  const gfx::Rect invalidate_rect(rect);
+#endif
+  damaged_rect_ = damaged_rect_.Union(invalidate_rect);
   // Ignore NPN_InvalidateRect calls with empty rects.  Also don't send an
   // invalidate if it's outside the clipping region, since if we did it won't
   // lead to a paint and we'll be stuck waiting forever for a DidPaint response.
   //
   // TODO(piman): There is a race condition here, because this test assumes
   // that when the paint actually occurs, the clip rect will not have changed.
   // This is not true because scrolling (or window resize) could occur and be
   // handled by the renderer before it receives the InvalidateRect message,
   // changing the clip rect and then not painting.
-  if (rect.IsEmpty() || !delegate_->GetClipRect().Intersects(rect))
+  if (invalidate_rect.IsEmpty() ||
+      !delegate_->GetClipRect().Intersects(invalidate_rect))
     return;
 
   // Only send a single InvalidateRect message at a time.  From DidPaint we
   // will dispatch an additional InvalidateRect message if necessary.
   if (!waiting_for_paint_) {
     waiting_for_paint_ = true;
     // Invalidates caused by calls to NPN_InvalidateRect/NPN_InvalidateRgn
     // need to be painted asynchronously as per the NPAPI spec.
     MessageLoop::current()->PostTask(FROM_HERE,
         runnable_method_factory_.NewRunnableMethod(
@@ skipping 489 matching lines @@
   while (index != resource_clients_.end()) {
     WebPluginResourceClient* client = (*index).second;
 
     if (client == resource_client) {
       resource_clients_.erase(index++);
     } else {
       index++;
     }
   }
 }