Implement OverlayPanels as SceneOverlays

chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.cc

Index: chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.cc
diff --git a/chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.cc b/chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.cc
index c4165671d201e49851263746e4f518f152f574fe..16e41d87fe21bc25004ea97e0616d2d87bd9f6f4 100644
--- a/chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.cc
+++ b/chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.cc
@@ -6,7 +6,9 @@
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
+#include "cc/layers/solid_color_layer.h"
 #include "chrome/browser/android/compositor/layer/reader_mode_layer.h"
+#include "content/public/browser/android/compositor.h"
 #include "content/public/browser/android/content_view_core.h"
 #include "jni/ReaderModeSceneLayer_jni.h"
 #include "ui/android/resources/resource_manager_impl.h"
@@ -16,7 +18,13 @@ namespace chrome {
 namespace android {
 
 ReaderModeSceneLayer::ReaderModeSceneLayer(JNIEnv* env, jobject jobj)
-    : SceneLayer(env, jobj) {
+    : SceneLayer(env, jobj),
+      base_page_brightness_(1.0f),
+      content_container_(cc::Layer::Create()) {
+  // Responsible for moving the base page without modifying the layer itself.
+  content_container_->SetIsDrawable(true);
+  content_container_->SetPosition(gfx::PointF(0.0f, 0.0f));
+  layer()->AddChild(content_container_);
 }
 
 ReaderModeSceneLayer::~ReaderModeSceneLayer() {
@@ -29,7 +37,11 @@ void ReaderModeSceneLayer::CreateReaderModeLayer(
   ui::ResourceManager* resource_manager =
       ui::ResourceManagerImpl::FromJavaObject(jresource_manager);
   reader_mode_layer_ = ReaderModeLayer::Create(resource_manager);
-  layer_->AddChild(reader_mode_layer_->layer());
+
+  // The Reader Mode layer is initially invisible.
+  reader_mode_layer_->layer()->SetHideLayerAndSubtree(true);
+
+  layer()->AddChild(reader_mode_layer_->layer());
 }
 
 void ReaderModeSceneLayer::SetResourceIds(
@@ -53,6 +65,8 @@ void ReaderModeSceneLayer::Update(
     JNIEnv* env,
     const JavaParamRef<jobject>& object,
     jfloat dp_to_px,
+    jfloat base_page_brightness,
+    jfloat base_page_offset,
     const JavaParamRef<jobject>& jcontent_view_core,
     jfloat panel_X,
     jfloat panel_y,
@@ -73,6 +87,20 @@ void ReaderModeSceneLayer::Update(
                           : content::ContentViewCore::GetNativeContentViewCore(
                                 env, jcontent_view_core);
 
+  // Fade the base page out.
+  if (base_page_brightness_ != base_page_brightness) {
+    base_page_brightness_ = base_page_brightness;
+    cc::FilterOperations filters;
+    if (base_page_brightness < 1.f) {
+      filters.Append(
+          cc::FilterOperation::CreateBrightnessFilter(base_page_brightness));
+    }
+    content_container_->SetFilters(filters);
+  }
+
+  // Move the base page contents up.
+  content_container_->SetPosition(gfx::PointF(0.0f, base_page_offset));
+
   reader_mode_layer_->SetProperties(
       dp_to_px,
       content_view_core,
@@ -87,6 +115,36 @@ void ReaderModeSceneLayer::Update(
       bar_border_height,
       bar_shadow_visible,
       bar_shadow_opacity);
+
+  // Make the layer visible if it is not already.
+  reader_mode_layer_->layer()->SetHideLayerAndSubtree(false);
+}
+
+void ReaderModeSceneLayer::SetContentTree(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& jobj,
+    const JavaParamRef<jobject>& jcontent_tree) {
+  SceneLayer* content_tree = FromJavaObject(env, jcontent_tree);
+  if (!content_tree || !content_tree->layer()) return;
+
+  if (!content_tree->layer()->parent()
+      || (content_tree->layer()->parent()->id() != content_container_->id())) {
+    content_container_->AddChild(content_tree->layer());
+  }
+}
+
+void ReaderModeSceneLayer::HideTree(JNIEnv* env,
+    const JavaParamRef<jobject>& jobj) {
+  // TODO(mdjones): Create super class for this logic.
+  if (reader_mode_layer_) {
+    reader_mode_layer_->layer()->SetHideLayerAndSubtree(true);
+  }
+  // Reset base page brightness.
+  cc::FilterOperations filters;
+  filters.Append(cc::FilterOperation::CreateBrightnessFilter(1.0f));
+  content_container_->SetFilters(filters);
+  // Reset base page offset.
+  content_container_->SetPosition(gfx::PointF(0.0f, 0.0f));
 }
 
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& jobj) {