Support bottom-right anchored fixed-position elements during a pinch gesture

cc/layers/layer_impl.h

 // Copyright 2011 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_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <string>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/animation/layer_animation_value_observer.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/region.h"
 #include "cc/base/scoped_ptr_vector.h"
 #include "cc/input/input_handler.h"
 #include "cc/layers/draw_properties.h"
 #include "cc/layers/layer_lists.h"
+#include "cc/layers/layer_position_constraint.h"
 #include "cc/layers/render_surface_impl.h"
 #include "cc/quads/render_pass.h"
 #include "cc/quads/shared_quad_state.h"
 #include "cc/resources/resource_provider.h"
 #include "skia/ext/refptr.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebFilterOperations.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "ui/gfx/rect.h"
@@ skipping 119 matching lines @@
   float opacity() const { return opacity_; }
   bool OpacityIsAnimating() const;
   bool OpacityIsAnimatingOnImplOnly() const;
 
   void SetPosition(gfx::PointF position);
   gfx::PointF position() const { return position_; }
 
   void SetIsContainerForFixedPositionLayers(bool container) {
     is_container_for_fixed_position_layers_ = container;
   }
-  bool is_container_for_fixed_position_layers() const {
+  // This is a non-trivial function in Layer.
+  bool IsContainerForFixedPositionLayers() const {
     return is_container_for_fixed_position_layers_;
   }
 
-  void SetFixedToContainerLayer(bool fixed) {
-    fixed_to_container_layer_ = fixed;
+  void SetFixedContainerSizeDelta(const gfx::Vector2dF& delta) {
+    fixed_container_size_delta_ = delta;
   }
-  bool fixed_to_container_layer() const { return fixed_to_container_layer_; }
+  const gfx::Vector2dF& fixed_container_size_delta() const {
+    return fixed_container_size_delta_;
+  }
+
+  void SetPositionConstraint(const LayerPositionConstraint& constraint) {
+    position_constraint_ = constraint;
+  }
+  const LayerPositionConstraint& position_constraint() const {
+    return position_constraint_;
+  }
 
   void SetPreserves3d(bool preserves_3d);
   bool preserves_3d() const { return preserves_3d_; }
 
   void SetUseParentBackfaceVisibility(bool use) {
     use_parent_backface_visibility_ = use;
   }
   bool use_parent_backface_visibility() const {
     return use_parent_backface_visibility_;
   }
@@ skipping 290 matching lines @@
   bool use_parent_backface_visibility_;
   bool draw_checkerboard_for_missing_tiles_;
   gfx::Transform sublayer_transform_;
   gfx::Transform transform_;
 
   bool draws_content_;
   bool force_render_surface_;
 
   // Set for the layer that other layers are fixed to.
   bool is_container_for_fixed_position_layers_;
-  // This is true if the layer should be fixed to the closest ancestor
-  // container.
-  bool fixed_to_container_layer_;
+  // This property is effective when
+  // is_container_for_fixed_position_layers_ == true,
+  gfx::Vector2dF fixed_container_size_delta_;
+
+  LayerPositionConstraint position_constraint_;
 
   gfx::Vector2dF scroll_delta_;
   gfx::Vector2d sent_scroll_delta_;
   gfx::Vector2d max_scroll_offset_;
   gfx::Transform impl_transform_;
   gfx::Vector2dF last_scroll_offset_;
 
   // The global depth value of the center of the layer. This value is used
   // to sort layers from back to front.
   float draw_depth_;
@@ skipping 28 matching lines @@
   // Group of properties that need to be computed based on the layer tree
   // hierarchy before layers can be drawn.
   DrawProperties<LayerImpl, RenderSurfaceImpl> draw_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_