Repaint overlay scrollbar if resource is disposed.

cc/layers/scrollbar_layer_unittest.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 <stddef.h>
 
 #include <unordered_map>
 
 #include "base/memory/ptr_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "cc/animation/animation_host.h"
 #include "cc/input/scrollbar_animation_controller.h"
 #include "cc/layers/append_quads_data.h"
+#include "cc/layers/painted_overlay_scrollbar_layer.h"
 #include "cc/layers/painted_scrollbar_layer.h"
 #include "cc/layers/painted_scrollbar_layer_impl.h"
 #include "cc/layers/scrollbar_layer_interface.h"
 #include "cc/layers/solid_color_scrollbar_layer.h"
 #include "cc/layers/solid_color_scrollbar_layer_impl.h"
 #include "cc/quads/solid_color_draw_quad.h"
 #include "cc/resources/ui_resource_manager.h"
 #include "cc/test/fake_impl_task_runner_provider.h"
 #include "cc/test/fake_layer_tree_host.h"
 #include "cc/test/fake_layer_tree_host_client.h"
@@ skipping 144 matching lines @@
   FakeResourceTrackingUIResourceManager* fake_ui_resource_manager_;
   FakeLayerTreeHostClient fake_client_;
   StubLayerTreeHostSingleThreadClient single_thread_client_;
   TestTaskGraphRunner task_graph_runner_;
   LayerTreeSettings layer_tree_settings_;
   std::unique_ptr<AnimationHost> animation_host_;
   std::unique_ptr<FakeLayerTreeHost> layer_tree_host_;
   int scrollbar_layer_id_;
 };
 
+class FakePaintedOverlayScrollbar : public FakeScrollbar {
+ public:
+  FakePaintedOverlayScrollbar() : FakeScrollbar(true, true, true) {}
+  bool UsesNinePatchThumbResource() const override { return true; }
+  gfx::Size NinePatchThumbCanvasSize() const override {
+    return gfx::Size(3, 3);
+  }
+  gfx::Rect NinePatchThumbAperture() const override {
+    return gfx::Rect(1, 1, 1, 1);
+  }
+};
+
+// Test that a painted overlay scrollbar will repaint and recrate its resource
+// after its been disposed, even if Blink doesn't think it requires a repaint.
+// crbug.com/704656.
+TEST_F(ScrollbarLayerTest, RepaintOverlayWhenResourceDisposed) {
+  scoped_refptr<Layer> layer_tree_root = Layer::Create();
+  scoped_refptr<Layer> content_layer = Layer::Create();
+  std::unique_ptr<FakePaintedOverlayScrollbar> scrollbar(
+      new FakePaintedOverlayScrollbar);
+  FakePaintedOverlayScrollbar* fake_scrollbar = scrollbar.get();
+  scoped_refptr<PaintedOverlayScrollbarLayer> scrollbar_layer =
+      PaintedOverlayScrollbarLayer::Create(std::move(scrollbar),
+                                           layer_tree_root->id());
+
+  // Setup.
+  {
+    layer_tree_root->AddChild(content_layer);
+    layer_tree_root->AddChild(scrollbar_layer);
+    layer_tree_host_->SetRootLayer(layer_tree_root);
+    scrollbar_layer->SetIsDrawable(true);
+    scrollbar_layer->SetBounds(gfx::Size(100, 100));
+    layer_tree_root->SetBounds(gfx::Size(100, 200));
+    content_layer->SetBounds(gfx::Size(100, 200));
+    scrollbar_layer->set_visible_layer_rect(gfx::Rect(0, 0, 100, 200));
+    scrollbar_layer->SavePaintProperties();
+  }
+
+  // First call to update should create a resource. The scrollbar itself thinks
+  // it needs a repaint.
+  {
+    fake_scrollbar->set_needs_paint_thumb(true);
+    EXPECT_EQ(0u, fake_ui_resource_manager_->UIResourceCount());
+    EXPECT_TRUE(scrollbar_layer->Update());
+    EXPECT_EQ(1u, fake_ui_resource_manager_->UIResourceCount());
+  }
+
+  // Now the scrollbar has been painted and nothing else has changed, calling
+  // Update() shouldn't have an effect.
+  {
+    fake_scrollbar->set_needs_paint_thumb(false);
+    EXPECT_FALSE(scrollbar_layer->Update());
+    EXPECT_EQ(1u, fake_ui_resource_manager_->UIResourceCount());
+  }
+
+  // Detach and reattach the LayerTreeHost (this can happen during tree
+  // reconstruction). This should cause the UIResource for the scrollbar to be
+  // disposed but the scrollbar itself hasn't changed so it reports that no
+  // repaint is needed. An Update should cause us to recreate the resource
+  // though.
+  {
+    scrollbar_layer->SetLayerTreeHost(nullptr);
+    scrollbar_layer->SetLayerTreeHost(layer_tree_host_.get());
+    EXPECT_EQ(0u, fake_ui_resource_manager_->UIResourceCount());
+    EXPECT_TRUE(scrollbar_layer->Update());
+    EXPECT_EQ(1u, fake_ui_resource_manager_->UIResourceCount());
+  }
+}
+
 TEST_F(ScrollbarLayerTest, ShouldScrollNonOverlayOnMainThread) {
   // Create and attach a non-overlay scrollbar.
   std::unique_ptr<Scrollbar> scrollbar(new FakeScrollbar);
   LayerImpl* layer_impl_tree_root = LayerImplForScrollAreaAndScrollbar(
       layer_tree_host_.get(), std::move(scrollbar), false, false, 0, 0);
   PaintedScrollbarLayerImpl* scrollbar_layer_impl =
       static_cast<PaintedScrollbarLayerImpl*>(
           layer_impl_tree_root->layer_tree_impl()->LayerById(
               scrollbar_layer_id_));
   ScrollTree& scroll_tree =
@@ skipping 977 matching lines @@
   TestScale(gfx::Rect(1240, 0, 15, 1333), 2.7754839f);
   TestScale(gfx::Rect(1240, 0, 15, 677), 2.46677136f);
 
   // Horizontal Scrollbars.
   TestScale(gfx::Rect(0, 1240, 1333, 15), 2.7754839f);
   TestScale(gfx::Rect(0, 1240, 677, 15), 2.46677136f);
 }
 
 }  // namespace
 }  // namespace cc