Fix crash in taking a screenshot of a closed popup

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 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/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 780 matching lines @@
 }
 
 void RenderWidgetCompositor::BeginMainFrameNotExpectedSoon() {
   compositor_deps_->GetRendererScheduler()->BeginFrameNotExpectedSoon();
 }
 
 void RenderWidgetCompositor::Layout() {
   widget_->webwidget()->layout();
 
   if (temporary_copy_output_request_) {
-    DCHECK(layer_tree_host_->root_layer());
-    layer_tree_host_->root_layer()->RequestCopyOfOutput(
-        temporary_copy_output_request_.Pass());
+    // For WebViewImpl cases, this will always have a root layer.
+    // For other widgets, the widget may be closed before servicing this
+    // request, so ignore it.
+    if (cc::Layer* root_layer = layer_tree_host_->root_layer())
+      root_layer->RequestCopyOfOutput(temporary_copy_output_request_.Pass());
+    else
+      temporary_copy_output_request_->SendEmptyResult();
+      temporary_copy_output_request_ = nullptr;

[piman, 2015/03/26 23:09:58]

nit: wrong indent, or did you forget brackets?
(it doesn't appear to make a functional difference)

[enne (OOO), 2015/03/27 17:40:52]

Last minute edit; forgot brackets.  <_<

*blush*

   }
 }
 
 void RenderWidgetCompositor::ApplyViewportDeltas(
     const gfx::Vector2dF& inner_delta,
     const gfx::Vector2dF& outer_delta,
     const gfx::Vector2dF& elastic_overscroll_delta,
     float page_scale,
     float top_controls_delta) {
   widget_->webwidget()->applyViewportDeltas(
@@ skipping 96 matching lines @@
   cc::ContextProvider* provider =
       compositor_deps_->GetSharedMainThreadContextProvider();
   // provider can be NULL after the GPU process crashed enough times and we
   // don't want to restart it any more (falling back to software).
   if (!provider)
     return;
   provider->ContextGL()->RateLimitOffscreenContextCHROMIUM();
 }
 
 }  // namespace content