When zooming, webkit reports width and height as if the zoom wasn't there (by...

chrome/renderer/render_view.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_view.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 3478 matching lines @@
   // be put in that mode by getting a |ViewMsg_EnablePreferredSizeChangedMode|
   // message.
   if (!send_preferred_size_changes_ || !webview())
     return;
 
   // WebCore likes to tell us things have changed even when they haven't, so
   // cache the width and height and only send the IPC message when we're sure
   // they're different.
   gfx::Size size(webview()->mainFrame()->contentsPreferredWidth(),
                  webview()->mainFrame()->documentElementScrollHeight());
+  // In the presence of zoom, these sizes are still reported as if unzoomed,
+  // so we need to adjust.
+  double zoom_factor = WebView::zoomLevelToZoomFactor(webview()->zoomLevel());
+  size.set_width(static_cast<int>(size.width() * zoom_factor));
+  size.set_height(static_cast<int>(size.height() * zoom_factor));
+
   if (size == preferred_size_)
     return;
 
   preferred_size_ = size;
   Send(new ViewHostMsg_DidContentsPreferredSizeChange(routing_id_,
                                                       preferred_size_));
 }
 
 void RenderView::didChangeScrollOffset(WebFrame* frame) {
   StartNavStateSyncTimerIfNecessary();
@@ skipping 2477 matching lines @@
 }
 
 void RenderView::OnAsyncFileOpened(base::PlatformFileError error_code,
                                    IPC::PlatformFileForTransit file_for_transit,
                                    int message_id) {
   pepper_delegate_.OnAsyncFileOpened(
       error_code,
       IPC::PlatformFileForTransitToPlatformFile(file_for_transit),
       message_id);
 }