Implement OverlayPanels as SceneOverlays

chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/ReaderModeSceneLayer.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/ReaderModeSceneLayer.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/ReaderModeSceneLayer.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/ReaderModeSceneLayer.java
index 157c5f04298c4dff43d45952795dd4762d8c32c6..b30a75ae6c403444395cb072060f8b0d0118366b 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/ReaderModeSceneLayer.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/ReaderModeSceneLayer.java
@@ -14,7 +14,7 @@ import org.chromium.ui.resources.ResourceManager;
  * A SceneLayer to render layers for Reader Mode.
  */
 @JNINamespace("chrome::android")
-public class ReaderModeSceneLayer extends SceneLayer {
+public class ReaderModeSceneLayer extends SceneOverlayLayer {
 
     /** Pointer to native ReaderModeSceneLayer. */
     private long mNativePtr;
@@ -55,9 +55,12 @@ public class ReaderModeSceneLayer extends SceneLayer {
         }
 
         // Don't try to update the layer if not initialized.
-        if (!mIsInitialized) return;
+        if (!mIsInitialized || !panel.isShowing()) return;
+
         nativeUpdate(mNativePtr,
                 mDpToPx,
+                panel.getBasePageBrightness(),
+                panel.getBasePageY() * mDpToPx,
                 panel.getContentViewCore(),
                 panel.getOffsetX() * mDpToPx,
                 panel.getOffsetY() * mDpToPx,
@@ -73,6 +76,19 @@ public class ReaderModeSceneLayer extends SceneLayer {
     }
 
     @Override
+    public void setContentTree(SceneLayer contentTree) {
+        if (!mIsInitialized) return;
+        nativeSetContentTree(mNativePtr, contentTree);
+    }
+
+    /**
+     * Hide the layer tree; for use if the panel is not being shown.
+     */
+    public void hideTree() {
+        nativeHideTree(mNativePtr);
+    }
+
+    @Override
     protected void initializeNative() {
         if (mNativePtr == 0) {
             mNativePtr = nativeInit();
@@ -94,6 +110,11 @@ public class ReaderModeSceneLayer extends SceneLayer {
     private native void nativeCreateReaderModeLayer(
             long nativeReaderModeSceneLayer,
             ResourceManager resourceManager);
+    private native void nativeSetContentTree(
+            long nativeReaderModeSceneLayer,
+            SceneLayer contentTree);
+    private native void nativeHideTree(
+            long nativeReaderModeSceneLayer);
     private native void nativeSetResourceIds(
             long nativeReaderModeSceneLayer,
             int barTextResourceId,
@@ -104,6 +125,8 @@ public class ReaderModeSceneLayer extends SceneLayer {
     private native void nativeUpdate(
             long nativeReaderModeSceneLayer,
             float dpToPx,
+            float basePageBrightness,
+            float basePageYOffset,
             ContentViewCore contentViewCore,
             float panelX,
             float panelY,