From 34f42fdecdf380d82f2be32b3564517002cc2112 Mon Sep 17 00:00:00 2001
From: Huihong Luo <huisinro@google.com>
Date: Mon, 3 May 2021 14:47:36 -0700
Subject: Fix z-order for webview surface control

Set the root surface control transparent, and set the z order of the newly created child surface control to -1.
A new callback is needed to update root surface control in sync from Java side.

Bug: 186750329
Test: use latest APKs from Webview team, play a video, mini toolbar should be visible
Change-Id: I0b37ee8f83fd2b41ff4f2856dbadd31ff6170baf
---
 core/java/android/view/ViewRootImpl.java | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

(limited to 'core/java/android/view/ViewRootImpl.java')

diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index d42e0c367763..cf8c746d6ecb 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -461,6 +461,9 @@ public final class ViewRootImpl implements ViewParent,
     protected final ViewFrameInfo mViewFrameInfo = new ViewFrameInfo();
     private final InputEventAssigner mInputEventAssigner = new InputEventAssigner();
 
+    // Set to true if mSurfaceControl is used for Webview Overlay
+    private boolean mIsForWebviewOverlay;
+
     /**
      * Update the Choreographer's FrameInfo object with the timing information for the current
      * ViewRootImpl instance. Erase the data in the current ViewFrameInfo to prepare for the next
@@ -1374,6 +1377,23 @@ public final class ViewRootImpl implements ViewParent,
         mAttachInfo.mThreadedRenderer.setASurfaceTransactionCallback(callback);
     }
 
+    /**
+     * Register a callback to be executed when Webview overlay needs a surface control.
+     * This callback will be executed on RenderThread worker thread, and released inside native code
+     * when CanvasContext is destroyed.
+     */
+    private void addPrepareSurfaceControlForWebviewCallback() {
+        HardwareRenderer.PrepareSurfaceControlForWebviewCallback callback = () -> {
+            // make mSurfaceControl transparent, so child surface controls are visible
+            if (mIsForWebviewOverlay) return;
+            synchronized (ViewRootImpl.this) {
+                mIsForWebviewOverlay = true;
+            }
+            mTransaction.setOpaque(mSurfaceControl, false).apply();
+        };
+        mAttachInfo.mThreadedRenderer.setPrepareSurfaceControlForWebviewCallback(callback);
+    }
+
     @UnsupportedAppUsage
     private void enableHardwareAcceleration(WindowManager.LayoutParams attrs) {
         mAttachInfo.mHardwareAccelerated = false;
@@ -1418,6 +1438,7 @@ public final class ViewRootImpl implements ViewParent,
                     if (mHardwareRendererObserver != null) {
                         mAttachInfo.mThreadedRenderer.addObserver(mHardwareRendererObserver);
                     }
+                    addPrepareSurfaceControlForWebviewCallback();
                     addASurfaceTransactionCallback();
                     mAttachInfo.mThreadedRenderer.setSurfaceControl(mSurfaceControl);
                 }
@@ -7743,6 +7764,7 @@ public final class ViewRootImpl implements ViewParent,
                 }
             }
             if (mAttachInfo.mThreadedRenderer != null) {
+                addPrepareSurfaceControlForWebviewCallback();
                 addASurfaceTransactionCallback();
                 mAttachInfo.mThreadedRenderer.setSurfaceControl(mSurfaceControl);
             }
@@ -7790,7 +7812,14 @@ public final class ViewRootImpl implements ViewParent,
             return;
         }
 
-        mTransaction.setOpaque(mSurfaceControl, opaque).apply();
+        synchronized (this) {
+            if (mIsForWebviewOverlay) {
+                mIsSurfaceOpaque = false;
+                return;
+            }
+            mTransaction.setOpaque(mSurfaceControl, opaque).apply();
+        }
+
         mIsSurfaceOpaque = opaque;
     }
 
-- 
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