Use nine-patch resource for drawing Aura overlay scrollbar thumb.

cc/quads/nine_patch_generator.h

-// Copyright 2012 The Chromium Authors. All rights reserved.
+// Copyright 2016 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.
 
-#ifndef CC_LAYERS_NINE_PATCH_LAYER_IMPL_H_
-#define CC_LAYERS_NINE_PATCH_LAYER_IMPL_H_
+#ifndef CC_QUADS_NINE_PATCH_GENERATOR_H_
+#define CC_QUADS_NINE_PATCH_GENERATOR_H_
 
 #include <string>
+#include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "cc/base/cc_export.h"
-#include "cc/layers/layer_impl.h"
-#include "cc/layers/ui_resource_layer_impl.h"
-#include "cc/resources/resource_provider.h"
-#include "cc/resources/ui_resource_client.h"
+#include "cc/base/resource_id.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace cc {
 
-class CC_EXPORT NinePatchLayerImpl : public UIResourceLayerImpl {
+class CC_EXPORT NinePatchGenerator {
  public:
-  static std::unique_ptr<NinePatchLayerImpl> Create(LayerTreeImpl* tree_impl,
-                                                    int id) {
-    return base::WrapUnique(new NinePatchLayerImpl(tree_impl, id));
-  }
-  ~NinePatchLayerImpl() override;
+  class Patch {
+   public:
+    Patch(const gfx::RectF& image_rect,
+          const gfx::Size& total_image_bounds,
+          const gfx::RectF& output_rect);
+
+    gfx::RectF image_rect;
+    gfx::RectF normalized_image_rect;
+    gfx::RectF output_rect;
+  };
+
+  NinePatchGenerator();
 
   // The bitmap stretches out the bounds of the layer.  The following picture
   // illustrates the parameters associated with the dimensions.
   //
   // Layer space layout
   //
   // --------------------------------
   // |         :    :               |
   // |         J    C               |
   // |         :    :               |
@@ skipping 27 matching lines @@
   // :                      |
   // :                      |
   // :                      |
   // ------------------------
   //
   // |image_bounds| = (W, H)
   // |image_aperture| = (X, Y, P, Q)
   // |border| = (A, C, A + B, C + D)
   // |occlusion_rectangle| = (I, J, K, L)
   // |fill_center| indicates whether to draw the center quad or not.
-  void SetLayout(const gfx::Rect& image_aperture,
+  bool SetLayout(const gfx::Size& image_bounds,
+                 const gfx::Size& output_bounds,
+                 const gfx::Rect& image_aperture,
                  const gfx::Rect& border,
-                 const gfx::Rect& layer_occlusion,
-                 bool fill_center,
-                 bool nearest_neighbor);
+                 const gfx::Rect& output_occlusion,
+                 bool fill_center);
 
-  std::unique_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
-  void PushPropertiesTo(LayerImpl* layer) override;
+  std::vector<Patch> GeneratePatches() const;
 
-  void AppendQuads(RenderPass* render_pass,
-                   AppendQuadsData* append_quads_data) override;
-
-  std::unique_ptr<base::DictionaryValue> LayerTreeAsJson() override;
-
- protected:
-  NinePatchLayerImpl(LayerTreeImpl* tree_impl, int id);
+  void AsJson(base::DictionaryValue* dictionary) const;
 
  private:
-  class Patch {
-   public:
-    Patch(const gfx::RectF& image_rect, const gfx::RectF& layer_rect);
-
-    gfx::RectF image_rect;
-    gfx::RectF layer_rect;
-  };
-
-  const char* LayerTypeAsString() const override;
-
   void CheckGeometryLimitations();
 
   std::vector<Patch> ComputeQuadsWithOcclusion() const;
   std::vector<Patch> ComputeQuadsWithoutOcclusion() const;
 
-  // The transparent center region that shows the parent layer's contents in
-  // image space.
+  // The center patch in image space.
   gfx::Rect image_aperture_;
 
   // An inset border that the patches will be mapped to.
   gfx::Rect border_;
 
+  gfx::Size image_bounds_;
+  gfx::Size output_bounds_;
+
   bool fill_center_;
 
-  bool nearest_neighbor_;
-
-  gfx::Rect layer_occlusion_;
-
-  DISALLOW_COPY_AND_ASSIGN(NinePatchLayerImpl);
+  gfx::Rect output_occlusion_;
 };
 
 }  // namespace cc
 
-#endif  // CC_LAYERS_NINE_PATCH_LAYER_IMPL_H_
+#endif  // CC_QUADS_NINE_PATCH_GENERATOR_H_