Check for null return from GetNativeView().

ui/keyboard/content/keyboard_ui_content.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 "ui/keyboard/content/keyboard_ui_content.h"
 
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/values.h"
 #include "content/public/browser/render_widget_host.h"
@@ skipping 143 matching lines @@
 void KeyboardUIContent::LoadSystemKeyboard() {
   DCHECK(keyboard_contents_);
   if (keyboard_contents_->GetURL() != default_url_) {
     // TODO(bshe): The height of system virtual keyboard and IME virtual
     // keyboard may different. The height needs to be restored too.
     LoadContents(default_url_);
   }
 }
 
 void KeyboardUIContent::UpdateInsetsForWindow(aura::Window* window) {
+  // Added while we determine if RenderWidgetHostViewChildFrame can be
+  // changed to always return a non-null value: https://crbug.com/644726 .
+  // If we cannot guarantee a non-null value, then this may need to stay.
+  if (!window)
+    return;

[Charlie Reis, 2016/09/07 20:27:16]

I think we probably shouldn't include this change.  There's no crashes that come
through this path (via OnWindowBoundsChanged), and it's not clear to me if it's
possible to crash this way.

In the interest of having a minimal change to merge, we should probably stick to
the InitInsets case below.

(All the non-InitInsets crashes come via ui::GestureRecognizerImpl, which is
likely a separate, pre-existing bug.)

[wjmaclean, 2016/09/07 20:40:57]

Done.

+
   aura::Window* keyboard_container =
       keyboard_controller()->GetContainerWindow();
   if (!ShouldWindowOverscroll(window))
     return;
 
   std::unique_ptr<content::RenderWidgetHostIterator> widgets(
       content::RenderWidgetHost::GetRenderWidgetHosts());
   while (content::RenderWidgetHost* widget = widgets->GetNextHost()) {
     content::RenderWidgetHostView* view = widget->GetView();
     if (view && window->Contains(view->GetNativeView())) {
@@ skipping 57 matching lines @@
   // TODO(kevers): Add EnvObserver to properly initialize insets if a
   // window is created while the keyboard is visible.
   std::unique_ptr<content::RenderWidgetHostIterator> widgets(
       content::RenderWidgetHost::GetRenderWidgetHosts());
   while (content::RenderWidgetHost* widget = widgets->GetNextHost()) {
     content::RenderWidgetHostView* view = widget->GetView();
     // Can be NULL, e.g. if the RenderWidget is being destroyed or
     // the render process crashed.
     if (view) {
       aura::Window* window = view->GetNativeView();
+      // Added while we determine if RenderWidgetHostViewChildFrame can be
+      // changed to always return a non-null value: https://crbug.com/644726 .
+      // If we cannot guarantee a non-null value, then this may need to stay.
+      if (!window)
+        return;

[Charlie Reis, 2016/09/07 20:27:16]

This needs to be a continue and not an early return, right?  We still want to
iterate over the rest of them.

[wjmaclean, 2016/09/07 20:40:57]

Ooops, I saw the enclosing if() but missed the while().

Done.

+
       if (ShouldWindowOverscroll(window)) {
         gfx::Rect window_bounds = window->GetBoundsInScreen();
         gfx::Rect intersect = gfx::IntersectRects(window_bounds,
                                                   new_bounds);
         int overlap = intersect.height();
         if (overlap > 0 && overlap < window_bounds.height())
           view->SetInsets(gfx::Insets(0, 0, overlap, 0));
         else
           view->SetInsets(gfx::Insets());
         AddBoundsChangedObserver(window);
@@ skipping 72 matching lines @@
           keyboard_controller()->keyboard_visible());
 }
 
 void KeyboardUIContent::AddBoundsChangedObserver(aura::Window* window) {
   aura::Window* target_window = window ? window->GetToplevelWindow() : nullptr;
   if (target_window)
     window_bounds_observer_->AddObservedWindow(target_window);
 }
 
 }  // namespace keyboard