cc: Cleanup Layer::SetNeedsDisplayInRect

cc/layers/image_layer.cc

 // Copyright 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 "cc/layers/image_layer.h"
 
 #include "base/compiler_specific.h"
 #include "cc/resources/image_layer_updater.h"
 #include "cc/resources/layer_updater.h"
 #include "cc/resources/prioritized_resource.h"
@@ skipping 25 matching lines @@
 void ImageLayer::SetTexturePriorities(const PriorityCalculator& priority_calc) {
   // Update the tile data before creating all the layer's tiles.
   UpdateTileSizeAndTilingOption();
 
   TiledLayer::SetTexturePriorities(priority_calc);
 }
 
 bool ImageLayer::Update(ResourceUpdateQueue* queue,
                         const OcclusionTracker* occlusion) {
   CreateUpdaterIfNeeded();
-  if (needs_display_) {
-    updater_->set_bitmap(bitmap_);
+  if (!updater_->UsingBitmap(bitmap_)) {

[enne (OOO), 2013/07/30 20:01:27]

The reason this code was broken before was that ImageLayer::SetBitmap above was
calling SetNeedsDisplay() when the bounds of the layer was empty.  This
prevented needs_display_ from getting set to true, causing the tile size to not
be updated in this conditional.  The tile size being zero means that we were
requesting shared memory of size zero which blew up.

This code is really trying to check that the bitmap has changed, and so check
this explicitly.  It's also a little sketchy that it was unsetting
needs_display_ here.

+    updater_->SetBitmap(bitmap_);
     UpdateTileSizeAndTilingOption();
     InvalidateContentRect(gfx::Rect(content_bounds()));
-    needs_display_ = false;
   }
   return TiledLayer::Update(queue, occlusion);
 }
 
 void ImageLayer::CreateUpdaterIfNeeded() {
   if (updater_.get())
     return;
 
   updater_ = ImageLayerUpdater::Create();
   GLenum texture_format =
@@ skipping 27 matching lines @@
   return static_cast<float>(bitmap_.width()) / bounds().width();
 }
 
 float ImageLayer::ImageContentsScaleY() const {
   if (bounds().IsEmpty() || bitmap_.height() == 0)
     return 1;
   return static_cast<float>(bitmap_.height()) / bounds().height();
 }
 
 }  // namespace cc