cc: Remove SetNeedsUpdate function from cc::Layer

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index c0425180ad777b2a0bfe41e6dda4852e1f7b20a1..dc909e1a0c76bbfd3aea1abcfde2b6891508fb36 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -43,6 +43,7 @@
 #include "cc/layers/painted_scrollbar_layer.h"
 #include "cc/resources/ui_resource_manager.h"
 #include "cc/trees/draw_property_utils.h"
+#include "cc/trees/effect_node.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_host_impl.h"
@@ -52,6 +53,7 @@
 #include "cc/trees/proxy_main.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/swap_promise_manager.h"
+#include "cc/trees/transform_node.h"
 #include "cc/trees/tree_synchronizer.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/vector2d_conversions.h"
@@ -273,7 +275,7 @@ void LayerTreeHost::FinishCommitOnImplThread(
       frame_viewer_instrumentation::IsTracingLayerTreeSnapshots() &&
       root_layer()) {
     LayerTreeHostCommon::CallFunctionForEveryLayer(
-        this, [](Layer* layer) { layer->DidBeginTracing(); });
+        this, [](Layer* layer) { layer->SetNeedsPushProperties(); });

[danakj, 2017/02/24 00:52:38]

Can you transplant the comment about why we're doing this?

   }
 
   LayerTreeImpl* sync_tree = host_impl->sync_tree();
@@ -637,6 +639,8 @@ bool LayerTreeHost::DoUpdateLayers(Layer* root_layer) {
   LayerList update_layer_list;
 
   {
+    base::AutoReset<bool> update_property_trees(&in_update_property_trees_,
+                                                true);
     TRACE_EVENT0("cc",
                  "LayerTreeHostInProcess::UpdateLayers::BuildPropertyTrees");
     TRACE_EVENT0(
@@ -674,7 +678,7 @@ bool LayerTreeHost::DoUpdateLayers(Layer* root_layer) {
 
   bool content_is_suitable_for_gpu = true;
   bool did_paint_content =
-      UpdateLayers(update_layer_list, &content_is_suitable_for_gpu);
+      PaintContent(update_layer_list, &content_is_suitable_for_gpu);
 
   if (content_is_suitable_for_gpu) {
     ++num_consecutive_frames_suitable_for_gpu_;
@@ -991,7 +995,7 @@ size_t LayerTreeHost::NumLayers() const {
   return layer_id_map_.size();
 }
 
-bool LayerTreeHost::UpdateLayers(const LayerList& update_layer_list,
+bool LayerTreeHost::PaintContent(const LayerList& update_layer_list,
                                  bool* content_is_suitable_for_gpu) {
   base::AutoReset<bool> painting(&in_paint_layer_contents_, true);
   bool did_paint_content = false;
@@ -1210,7 +1214,24 @@ void LayerTreeHost::SetElementOpacityMutated(ElementId element_id,
                                              float opacity) {
   Layer* layer = LayerByElementId(element_id);
   DCHECK(layer);
+  DCHECK_GE(opacity, 0.f);
+  DCHECK_LE(opacity, 1.f);
   layer->OnOpacityAnimated(opacity);
+
+  if (property_trees_.IsInIdToIndexMap(PropertyTrees::TreeType::EFFECT,
+                                       layer->id())) {
+    DCHECK_EQ(layer->effect_tree_index(),
+              property_trees_.layer_id_to_effect_node_index[layer->id()]);
+    EffectNode* node =
+        property_trees_.effect_tree.Node(layer->effect_tree_index());
+    if (node->opacity == opacity)
+      return;
+
+    node->opacity = opacity;
+    property_trees_.effect_tree.set_needs_update(true);
+  }
+
+  SetNeedsUpdateLayers();
 }
 
 void LayerTreeHost::SetElementTransformMutated(
@@ -1220,6 +1241,21 @@ void LayerTreeHost::SetElementTransformMutated(
   Layer* layer = LayerByElementId(element_id);
   DCHECK(layer);
   layer->OnTransformAnimated(transform);
+  if (property_trees_.IsInIdToIndexMap(PropertyTrees::TreeType::TRANSFORM,

[danakj, 2017/02/24 00:52:38]

nit: maybe im being pedantic but can you make the whitespace story similar
between these two methods?

+                                       layer->id())) {
+    DCHECK_EQ(layer->transform_tree_index(),
+              property_trees_.layer_id_to_transform_node_index[layer->id()]);
+    TransformNode* node =
+        property_trees_.transform_tree.Node(layer->transform_tree_index());
+    if (node->local == transform)
+      return;
+
+    node->local = transform;
+    node->needs_local_transform_update = true;
+    node->has_potential_animation = true;
+    property_trees_.transform_tree.set_needs_update(true);
+  }
+  SetNeedsUpdateLayers();
 }
 
 void LayerTreeHost::SetElementScrollOffsetMutated(