Fixed PinchViewport getting resized to empty size

content/renderer/render_widget.cc

 // Copyright (c) 2012 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 "content/renderer/render_widget.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_synthetic_delay.h"
@@ skipping 637 matching lines @@
   if (!webwidget_)
     return;
 
   if (compositor_) {
     compositor_->setViewportSize(new_size, physical_backing_size);
     compositor_->SetOverdrawBottomHeight(overdraw_bottom_height);
   }
 
   physical_backing_size_ = physical_backing_size;
   overdraw_bottom_height_ = overdraw_bottom_height;
+  visible_viewport_size_ = visible_viewport_size;
   resizer_rect_ = resizer_rect;
 
   // NOTE: We may have entered fullscreen mode without changing our size.
   bool fullscreen_change = is_fullscreen_ != is_fullscreen;
   if (fullscreen_change)
     WillToggleFullscreen();
   is_fullscreen_ = is_fullscreen;
 
   if (size_ != new_size) {
     size_ = new_size;
@@ skipping 1440 matching lines @@
 
 void RenderWidget::RegisterSwappedOutChildFrame(RenderFrameImpl* frame) {
   swapped_out_frames_.AddObserver(frame);
 }
 
 void RenderWidget::UnregisterSwappedOutChildFrame(RenderFrameImpl* frame) {
   swapped_out_frames_.RemoveObserver(frame);
 }
 
 }  // namespace content