Fix crashes when NinePatchLayer doesn't have a resource.

cc/layers/nine_patch_layer.cc

 // Copyright 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 "cc/layers/nine_patch_layer.h"
 
 #include "cc/layers/nine_patch_layer_impl.h"
 #include "cc/resources/prioritized_resource.h"
 #include "cc/resources/resource_update.h"
 #include "cc/resources/resource_update_queue.h"
@@ skipping 53 matching lines @@
       (bitmap_dirty_ || resource_->texture()->resource_id() == 0)) {
     gfx::Rect content_rect(0, 0, bitmap_.width(), bitmap_.height());
     ResourceUpdate upload = ResourceUpdate::Create(resource_->texture(),
                                                    &bitmap_,
                                                    content_rect,
                                                    content_rect,
                                                    gfx::Vector2d());
     queue->AppendFullUpload(upload);
     bitmap_dirty_ = false;
     updated = true;
+    SetNeedsPushProperties();

[danakj, 2013/08/20 02:22:32]

Oh, this uses prioritized texture manager so it can't tell if it needs to push
properties until we're inside the BeginFrame :(

For tiled layer, we just push properties every frame:
https://code.google.com/p/chromium/codesearch#chromium/src/cc/layers/tiled_la...

We could do that here too, and file a bug to fix this with the UIResourceManager
(similar for scrollbar layers).

In fact, this value of updated seems wrong in the case that
NinePatchLayer::SetTexturePriorities() decides it can't support the texture
anymore and drops the resource_. The commit would be aborted in that case, even
though the resource id will no longer be valid. +enne

We should fix updated to be true in the right cases (ie also when the resource
was present last frame but dropped this frame). Then I think we could SNPP()
here if updated was true, rather than just setting it true all the time like
scrollbar/tiled layer, if you like.

[ccameron, 2013/08/20 09:43:47]

I've set it to be SNPP unconditionally for now.

   }
   return updated;
 }
 
 void NinePatchLayer::CreateUpdaterIfNeeded() {
   if (updater_.get())
     return;
 
   updater_ = ImageLayerUpdater::Create();
 }
@@ skipping 23 matching lines @@
 
   if (resource_) {
     DCHECK(!bitmap_.isNull());
     layer_impl->SetResourceId(resource_->texture()->resource_id());
     layer_impl->SetLayout(
         gfx::Size(bitmap_.width(), bitmap_.height()), image_aperture_);
   }
 }
 
 }  // namespace cc