compositor-worker: Introduce WebCompositorMutableState

cc/blink/web_mutable_state_impl.cc

+// Copyright 2015 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/blink/web_mutable_state_impl.h"
+
+#include "cc/animation/layer_tree_mutation.h"
+#include "cc/layers/layer_impl.h"
+#include "cc/trees/layer_tree_impl.h"
+
+namespace cc_blink {
+
+WebMutableStateImpl::WebMutableStateImpl(cc::LayerTreeMutation* mutation,
+                                         cc::LayerImpl* main_layer,
+                                         cc::LayerImpl* scroll_layer)
+    : mutation_(mutation),
+      main_layer_(main_layer),
+      scroll_layer_(scroll_layer) {}
+
+WebMutableStateImpl::~WebMutableStateImpl() {}
+
+double WebMutableStateImpl::getOpacity() const {
+  return main_layer_->opacity();
+}
+
+void WebMutableStateImpl::setOpacity(double opacity) {
+  if (!main_layer_)
+    return;
+  main_layer_->OnOpacityAnimated(opacity);
+  mutation_->SetOpacity(opacity);
+}
+
+const SkMatrix44& WebMutableStateImpl::getTransform() const {
+  static SkMatrix44 identity;
+  return main_layer_ ? main_layer_->transform().matrix() : identity;
+}
+
+void WebMutableStateImpl::setTransform(const SkMatrix44& matrix) {
+  if (!main_layer_)
+    return;
+  main_layer_->OnTransformAnimated(gfx::Transform(matrix));
+  mutation_->SetTransform(matrix);
+}
+
+double WebMutableStateImpl::getScrollLeft() const {
+  return scroll_layer_ ? scroll_layer_->CurrentScrollOffset().x() : 0.0;
+}
+
+void WebMutableStateImpl::setScrollLeft(double scroll_left) {
+  if (!scroll_layer_)
+    return;
+  gfx::ScrollOffset offset = scroll_layer_->CurrentScrollOffset();
+  offset.set_x(scroll_left);
+  scroll_layer_->OnScrollOffsetAnimated(offset);
+  mutation_->SetScrollLeft(scroll_left);
+}
+
+double WebMutableStateImpl::getScrollTop() const {
+  return scroll_layer_ ? scroll_layer_->CurrentScrollOffset().y() : 0.0;
+}
+
+void WebMutableStateImpl::setScrollTop(double scroll_top) {
+  if (!scroll_layer_)
+    return;
+  gfx::ScrollOffset offset = scroll_layer_->CurrentScrollOffset();
+  offset.set_y(scroll_top);
+  scroll_layer_->OnScrollOffsetAnimated(offset);
+  mutation_->SetScrollTop(scroll_top);
+}
+
+WebMutableStateProviderImpl::WebMutableStateProviderImpl(
+    cc::LayerTreeImpl* state,
+    cc::LayerTreeMutationMap* mutations)
+    : state_(state), mutations_(mutations) {}
+
+WebMutableStateProviderImpl::~WebMutableStateProviderImpl() {}
+
+blink::WebMutableState* WebMutableStateProviderImpl::getMutableStateFor(
+    uint64_t element_id) {
+  cc::LayerImpl* main_layer = nullptr;
+  cc::LayerImpl* scroll_layer = nullptr;
+  if (!state_->GetMutableLayers(element_id, &main_layer, &scroll_layer))
+    return nullptr;
+
+  return new WebMutableStateImpl(&(*mutations_)[element_id], main_layer,
+                                 scroll_layer);
+}
+
+}  // namespace cc_blink