Bug 1514253 - Create PanZoomController immediately in GeckoSession r=geckoview-reviewers,droeh#geckoview-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D14562

--HG--
extra : moz-landing-system : lando

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java

@@ -107,7 +107,7 @@ public class GeckoSession implements Parcelable {
     private boolean mShouldPinOnScreen;
 
     // All fields are accessed on UI thread only.
-    private PanZoomController mNPZC;
+    private PanZoomController mPanZoomController = new PanZoomController(this);
     private OverscrollEdgeEffect mOverscroll;
     private DynamicToolbarAnimator mToolbar;
     private CompositorController mController;
@@ -3658,13 +3658,7 @@ public class GeckoSession implements Parcelable {
     public @NonNull PanZoomController getPanZoomController() {
         ThreadUtils.assertOnUiThread();
 
-        if (mNPZC == null) {
-            mNPZC = new PanZoomController(this);
-            if (mAttachedCompositor) {
-                mCompositor.attachNPZC(mNPZC);
-            }
-        }
-        return mNPZC;
+        return mPanZoomController;
     }
 
     /**
@@ -4340,10 +4334,7 @@ public class GeckoSession implements Parcelable {
         }
 
         mAttachedCompositor = true;
-
-        if (mNPZC != null) {
-            mCompositor.attachNPZC(mNPZC);
-        }
+        mCompositor.attachNPZC(mPanZoomController);
 
         if (mSurface != null) {
             // If we have a valid surface, create the compositor now that we're attached.

widget/android/nsWindow.cpp

@@ -890,7 +890,14 @@ class nsWindow::LayerViewSupport final
     }
 
     MOZ_ASSERT(aNPZC);
-    MOZ_ASSERT(!mWindow->mNPZCSupport);
+
+    // We can have this situation if we get two GeckoViewSupport::Transfer()
+    // called before the first AttachNPZC() gets here. Just detach the current
+    // instance since that's what happens in GeckoViewSupport::Transfer() as
+    // well.
+    if (mWindow->mNPZCSupport) {
+      mWindow->mNPZCSupport.Detach(mWindow->mNPZCSupport->GetJavaNPZC());
+    }
 
     auto npzc = PanZoomController::LocalRef(
         jni::GetGeckoThreadEnv(), PanZoomController::Ref::From(aNPZC));