Bug 1229403 - Use existing states if possible when initializing GeckoView; r=snorp

This patch changes onAttachedToWindow in GeckoView, so that if we have
states that have been restored, we use those states for initialization
instead of creating new states (e.g. opening a new nsWindow). Because
the GLController instance is associated with the nsWindow instance, we
need to keep the GLController instance as part of our saved states. This
patch also adds a reattach method to GeckoView.Window, because
GeckoEditable needs to be notified when its target View changes.

mobile/android/base/java/org/mozilla/gecko/GeckoView.java

@@ -121,10 +121,14 @@ public class GeckoView extends LayerView
 
     @WrapForJNI
     private static final class Window extends JNIObject {
+        /* package */ final GLController glController = new GLController();
+
         static native void open(Window instance, GeckoView view, GLController glController,
                                 int width, int height);
+
         @Override protected native void disposeNative();
         native void close();
+        native void reattach(GeckoView view);
     }
 
     // Object to hold onto our nsWindow connection when GeckoView gets destroyed.
@@ -292,20 +296,28 @@ public class GeckoView extends LayerView
     {
         final DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
 
-        // TODO: reuse GLController when restoring state.
-        final GLController glController = new GLController();
+        if (window == null) {
+            // Open a new nsWindow if we didn't have one from before.
+            window = new Window();
 
             if (GeckoThread.isStateAtLeast(GeckoThread.State.PROFILE_READY)) {
-            Window.open(window, this, glController,
+                Window.open(window, this, window.glController,
                             metrics.widthPixels, metrics.heightPixels);
-
             } else {
                 GeckoThread.queueNativeCallUntil(GeckoThread.State.PROFILE_READY, Window.class,
-                    "open", window, GeckoView.class, this, glController,
+                        "open", window, GeckoView.class, this, window.glController,
                         metrics.widthPixels, metrics.heightPixels);
             }
+        } else {
+            if (GeckoThread.isStateAtLeast(GeckoThread.State.PROFILE_READY)) {
+                window.reattach(this);
+            } else {
+                GeckoThread.queueNativeCallUntil(GeckoThread.State.PROFILE_READY,
+                        window, "reattach", GeckoView.class, this);
+            }
+        }
 
-        setGLController(glController);
+        setGLController(window.glController);
         super.onAttachedToWindow();
     }
 

widget/android/GeneratedJNINatives.h

@@ -203,7 +203,11 @@ public:
 
         mozilla::jni::MakeNativeMethod<GeckoView::Window::Open_t>(
                 mozilla::jni::NativeStub<GeckoView::Window::Open_t, Impl>
-                ::template Wrap<&Impl::Open>)
+                ::template Wrap<&Impl::Open>),
+
+        mozilla::jni::MakeNativeMethod<GeckoView::Window::Reattach_t>(
+                mozilla::jni::NativeStub<GeckoView::Window::Reattach_t, Impl>
+                ::template Wrap<&Impl::Reattach>)
     };
 };
 

widget/android/GeneratedJNIWrappers.cpp

@@ -1113,6 +1113,17 @@ constexpr char GeckoView::Window::DisposeNative_t::signature[];
 constexpr char GeckoView::Window::Open_t::name[];
 constexpr char GeckoView::Window::Open_t::signature[];
 
+constexpr char GeckoView::Window::Reattach_t::name[];
+constexpr char GeckoView::Window::Reattach_t::signature[];
+
+constexpr char GeckoView::Window::GlController_t::name[];
+constexpr char GeckoView::Window::GlController_t::signature[];
+
+auto GeckoView::Window::GlController() const -> mozilla::jni::Object::LocalRef
+{
+    return mozilla::jni::Field<GlController_t>::Get(this, nullptr);
+}
+
 constexpr char PrefsHelper::name[];
 
 constexpr char PrefsHelper::GetPrefsById_t::name[];

widget/android/GeneratedJNIWrappers.h

@@ -2995,6 +2995,39 @@ public:
                 mozilla::jni::ExceptionMode::ABORT;
     };
 
+public:
+    struct Reattach_t {
+        typedef Window Owner;
+        typedef void ReturnType;
+        typedef void SetterType;
+        typedef mozilla::jni::Args<
+                GeckoView::Param> Args;
+        static constexpr char name[] = "reattach";
+        static constexpr char signature[] =
+                "(Lorg/mozilla/gecko/GeckoView;)V";
+        static const bool isStatic = false;
+        static const bool isMultithreaded = true;
+        static const mozilla::jni::ExceptionMode exceptionMode =
+                mozilla::jni::ExceptionMode::ABORT;
+    };
+
+public:
+    struct GlController_t {
+        typedef Window Owner;
+        typedef mozilla::jni::Object::LocalRef ReturnType;
+        typedef mozilla::jni::Object::Param SetterType;
+        typedef mozilla::jni::Args<> Args;
+        static constexpr char name[] = "glController";
+        static constexpr char signature[] =
+                "Lorg/mozilla/gecko/gfx/GLController;";
+        static const bool isStatic = false;
+        static const bool isMultithreaded = true;
+        static const mozilla::jni::ExceptionMode exceptionMode =
+                mozilla::jni::ExceptionMode::ABORT;
+    };
+
+    auto GlController() const -> mozilla::jni::Object::LocalRef;
+
 public:
     template<class Impl> class Natives;
 };

widget/android/nsWindow.cpp

@@ -144,10 +144,8 @@ NS_IMPL_ISUPPORTS(ContentCreationNotifier,
 // one.
 static nsTArray<nsWindow*> gTopLevelWindows;
 
-// FIXME: because we don't support separate nsWindow for each GeckoView
-// yet, we have to attach a new GeckoView to an existing nsWindow if it
-// exists. Eventually, an nsWindow will be opened/closed as each GeckoView
-// is created/destroyed.
+// FIXME: because we don't support multiple GeckoViews for every feature
+// yet, we have to default to a particular GeckoView for certain calls.
 static nsWindow* gGeckoViewWindow;
 
 static bool sFailedToCreateGLContext = false;
@@ -274,6 +272,9 @@ public:
     // Close and destroy the nsWindow.
     void Close();
 
+    // Reattach this nsWindow to a new GeckoView.
+    void Reattach(GeckoView::Param aView);
+
     /**
      * GeckoEditable methods
      */
@@ -649,21 +650,6 @@ nsWindow::GeckoViewSupport::Open(const jni::ClassObject::LocalRef& aCls,
     PROFILER_LABEL("nsWindow", "GeckoViewSupport::Open",
                    js::ProfileEntry::Category::OTHER);
 
-    if (gGeckoViewWindow) {
-        // Should have been created the first time.
-        MOZ_ASSERT(gGeckoViewWindow->mGeckoViewSupport);
-        gGeckoViewWindow->mGeckoViewSupport->Reattach(
-                GeckoView::Window::LocalRef(aCls.Env(), aWindow));
-
-        MOZ_ASSERT(gGeckoViewWindow->mGLControllerSupport);
-        gGeckoViewWindow->mGLControllerSupport->Reattach(GLController::LocalRef(
-                aCls.Env(), GLController::Ref::From(aGLController)));
-
-        // Associate our previous GeckoEditable with the new GeckoView.
-        gGeckoViewWindow->mGeckoViewSupport->mEditable->OnViewChange(aView);
-        return;
-    }
-
     nsCOMPtr<nsIWindowWatcher> ww = do_GetService(NS_WINDOWWATCHER_CONTRACTID);
     MOZ_ASSERT(ww);
 
@@ -729,6 +715,13 @@ nsWindow::GeckoViewSupport::Close()
     baseWindow->Destroy();
 }
 
+void
+nsWindow::GeckoViewSupport::Reattach(GeckoView::Param aView)
+{
+    // Associate our previous GeckoEditable with the new GeckoView.
+    mEditable->OnViewChange(aView);
+}
+
 void
 nsWindow::InitNatives()
 {