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..6a61e34e0767ffa9a712cf438f4618cd14d8b369 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 +18,12 @@ 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));
 }
 
 ReaderModeSceneLayer::~ReaderModeSceneLayer() {
@@ -29,7 +36,13 @@ 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);
+
+  // Add all layers to the tree; this is order dependent.
+  layer()->AddChild(content_container_);
+  layer()->AddChild(reader_mode_layer_->layer());
 }
 
 void ReaderModeSceneLayer::SetResourceIds(
@@ -53,6 +66,8 @@ 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 +88,19 @@ 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 +115,35 @@ 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) {
+  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));

[Theresa, 2016/04/21 21:22:39]

Does it make sense for this code (and some of the other duplicated code) to be
shared in an OverlaySceneLayer base class? Right not the duplicate code is
pretty limited, so I also think it's okay to keep the # of classes smaller. 

[pedro (no code reviews), 2016/04/22 02:11:05]

I also think moving duplicate code to a shared class is a good idea.

[mdjones, 2016/04/22 17:03:42]

This is something I'd like to address in a follow-up CL along with some of the
java changes I mentioned for pedro.

 }
 
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& jobj) {