Implement OverlayPanels as SceneOverlays

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

 // Copyright 2016 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 "chrome/browser/android/compositor/scene_layer/reader_mode_scene_layer.h"
 
 #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"
 #include "ui/gfx/android/java_bitmap.h"
 
 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() {
 }
 
 void ReaderModeSceneLayer::CreateReaderModeLayer(
     JNIEnv* env,
     const JavaParamRef<jobject>& object,
     const JavaParamRef<jobject>& jresource_manager) {
   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(
     JNIEnv* env,
     const JavaParamRef<jobject>& object,
     jint text_resource_id,
     jint bar_background_resource_id,
     jint bar_shadow_resource_id,
     jint panel_icon_resource_id,
     jint close_icon_resource_id) {
 
   reader_mode_layer_->SetResourceIds(
       text_resource_id,
       bar_background_resource_id,
       bar_shadow_resource_id,
       panel_icon_resource_id,
       close_icon_resource_id);
 }
 
 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,
     jfloat panel_width,
     jfloat panel_height,
     jfloat bar_margin_side,
     jfloat bar_height,
     jfloat text_opacity,
     jboolean bar_border_visible,
     jfloat bar_border_height,
     jboolean bar_shadow_visible,
     jfloat bar_shadow_opacity) {
   // NOTE(mdjones): It is possible to render the panel before content has been
   // created. If this is the case, do not attempt to access the ContentViewCore
   // and instead pass null.
   content::ContentViewCore* content_view_core =
       !jcontent_view_core ? NULL
                           : 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,
       panel_X,
       panel_y,
       panel_width,
       panel_height,
       bar_margin_side,
       bar_height,
       text_opacity,
       bar_border_visible,
       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) {
   // This will automatically bind to the Java object and pass ownership there.
   ReaderModeSceneLayer* reader_mode_scene_layer =
       new ReaderModeSceneLayer(env, jobj);
   return reinterpret_cast<intptr_t>(reader_mode_scene_layer);
 }
 
 bool RegisterReaderModeSceneLayer(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace android
 }  // namespace chrome