2 files changed, 57 insertions, 111 deletions

diff --git a/tools/sk_app/Window.cpp b/tools/sk_app/Window.cpp
index d7904fd8a7..436b6b9aa9 100644
--- a/tools/sk_app/Window.cpp
+++ b/tools/sk_app/Window.cpp
@@ -13,45 +13,7 @@
 
 namespace sk_app {
 
-static void default_backend_created_func(void* userData) {}
-
-static bool default_char_func(SkUnichar c, uint32_t modifiers, void* userData) {
-    return false;
-}
-
-static bool default_key_func(Window::Key key, Window::InputState state, uint32_t modifiers,
-                             void* userData) {
-    return false;
-}
-
-static bool default_mouse_func(int x, int y, Window::InputState state, uint32_t modifiers,
-                               void* userData) {
-    return false;
-}
-
-static bool default_mouse_wheel_func(float delta, uint32_t modifiers, void* userData) {
-    return false;
-}
-
-static bool default_touch_func(intptr_t owner, Window::InputState state, float x, float y,
-                               void* userData) {
-    return false;
-}
-
-static void default_ui_state_changed_func(
-        const SkString& stateName, const SkString& stateValue, void* userData) {}
-
-static void default_paint_func(SkCanvas*, void* userData) {}
-
-Window::Window() : fBackendCreatedFunc(default_backend_created_func)
-                 , fCharFunc(default_char_func)
-                 , fKeyFunc(default_key_func)
-                 , fMouseFunc(default_mouse_func)
-                 , fMouseWheelFunc(default_mouse_wheel_func)
-                 , fTouchFunc(default_touch_func)
-                 , fUIStateChangedFunc(default_ui_state_changed_func)
-                 , fPaintFunc(default_paint_func) {
-}
+Window::Window() {}
 
 void Window::detach() {
     delete fWindowContext;
@@ -59,31 +21,60 @@ void Window::detach() {
 }
 
 void Window::onBackendCreated() {
-    fBackendCreatedFunc(fBackendCreatedUserData);
+    for (int i = 0; i < fLayers.count(); ++i) {
+        fLayers[i]->onBackendCreated();
+    }
 }
 
 bool Window::onChar(SkUnichar c, uint32_t modifiers) {
-    return fCharFunc(c, modifiers, fCharUserData);
+    for (int i = fLayers.count() - 1; i >= 0; --i) {
+        if (fLayers[i]->onChar(c, modifiers)) {
+            return true;
+        }
+    }
+    return false;
 }
 
 bool Window::onKey(Key key, InputState state, uint32_t modifiers) {
-    return fKeyFunc(key, state, modifiers, fKeyUserData);
+    for (int i = fLayers.count() - 1; i >= 0; --i) {
+        if (fLayers[i]->onKey(key, state, modifiers)) {
+            return true;
+        }
+    }
+    return false;
 }
 
 bool Window::onMouse(int x, int y, InputState state, uint32_t modifiers) {
-    return fMouseFunc(x, y, state, modifiers, fMouseUserData);
+    for (int i = fLayers.count() - 1; i >= 0; --i) {
+        if (fLayers[i]->onMouse(x, y, state, modifiers)) {
+            return true;
+        }
+    }
+    return false;
 }
 
 bool Window::onMouseWheel(float delta, uint32_t modifiers) {
-    return fMouseWheelFunc(delta, modifiers, fMouseWheelUserData);
+    for (int i = fLayers.count() - 1; i >= 0; --i) {
+        if (fLayers[i]->onMouseWheel(delta, modifiers)) {
+            return true;
+        }
+    }
+    return false;
 }
 
 bool Window::onTouch(intptr_t owner, InputState state, float x, float y) {
-    return fTouchFunc(owner, state, x, y, fTouchUserData);
+    for (int i = fLayers.count() - 1; i >= 0; --i) {
+        if (fLayers[i]->onTouch(owner, state, x, y)) {
+            return true;
+        }
+    }
+    return false;
 }
 
 void Window::onUIStateChanged(const SkString& stateName, const SkString& stateValue) {
-    return fUIStateChangedFunc(stateName, stateValue, fUIStateChangedUserData);
+    for (int i = 0; i < fLayers.count(); ++i) {
+        fLayers[i]->onUIStateChanged(stateName, stateValue);
+    }
 }
 
 void Window::onPaint() {
@@ -96,7 +87,9 @@ void Window::onPaint() {
         // draw into the canvas of this surface
         SkCanvas* canvas = backbuffer->getCanvas();
 
-        fPaintFunc(canvas, fPaintUserData);
+        for (int i = 0; i < fLayers.count(); ++i) {
+            fLayers[i]->onPaint(canvas);
+        }
 
         canvas->flush();
 
diff --git a/tools/sk_app/Window.h b/tools/sk_app/Window.h
index 4d40780964..77478b598e 100644
--- a/tools/sk_app/Window.h
+++ b/tools/sk_app/Window.h
@@ -130,55 +130,23 @@ public:
         kMove_InputState   // only valid for mouse
     };
 
-    // return value of 'true' means 'I have handled this event'
-    typedef void(*OnBackendCreatedFunc)(void* userData);
-    typedef bool(*OnCharFunc)(SkUnichar c, uint32_t modifiers, void* userData);
-    typedef bool(*OnKeyFunc)(Key key, InputState state, uint32_t modifiers, void* userData);
-    typedef bool(*OnMouseFunc)(int x, int y, InputState state, uint32_t modifiers, void* userData);
-    typedef bool(*OnMouseWheelFunc)(float delta, uint32_t modifiers, void* userData);
-    typedef bool(*OnTouchFunc)(intptr_t owner, InputState state, float x, float y, void* userData);
-    typedef void(*OnUIStateChangedFunc)(
-            const SkString& stateName, const SkString& stateValue, void* userData);
-    typedef void(*OnPaintFunc)(SkCanvas*, void* userData);
-
-    void registerBackendCreatedFunc(OnBackendCreatedFunc func, void* userData) {
-        fBackendCreatedFunc = func;
-        fBackendCreatedUserData = userData;
-    }
-
-    void registerCharFunc(OnCharFunc func, void* userData) {
-        fCharFunc = func;
-        fCharUserData = userData;
-    }
-
-    void registerKeyFunc(OnKeyFunc func, void* userData) {
-        fKeyFunc = func;
-        fKeyUserData = userData;
-    }
-
-    void registerMouseFunc(OnMouseFunc func, void* userData) {
-        fMouseFunc = func;
-        fMouseUserData = userData;
-    }
-
-    void registerMouseWheelFunc(OnMouseWheelFunc func, void* userData) {
-        fMouseWheelFunc = func;
-        fMouseWheelUserData = userData;
-    }
-
-    void registerPaintFunc(OnPaintFunc func, void* userData) {
-        fPaintFunc = func;
-        fPaintUserData = userData;
-    }
-
-    void registerTouchFunc(OnTouchFunc func, void* userData) {
-        fTouchFunc = func;
-        fTouchUserData = userData;
-    }
+    class Layer {
+    public:
+        virtual ~Layer() = default;
+
+        // return value of 'true' means 'I have handled this event'
+        virtual void onBackendCreated() {}
+        virtual bool onChar(SkUnichar c, uint32_t modifiers) { return false; }
+        virtual bool onKey(Key key, InputState state, uint32_t modifiers) { return false; }
+        virtual bool onMouse(int x, int y, InputState state, uint32_t modifiers) { return false; }
+        virtual bool onMouseWheel(float delta, uint32_t modifiers) { return false; }
+        virtual bool onTouch(intptr_t owner, InputState state, float x, float y) { return false; }
+        virtual void onUIStateChanged(const SkString& stateName, const SkString& stateValue) {}
+        virtual void onPaint(SkCanvas*) {}
+    };
 
-    void registerUIStateChangedFunc(OnUIStateChangedFunc func, void* userData) {
-        fUIStateChangedFunc = func;
-        fUIStateChangedUserData = userData;
+    void pushLayer(Layer* layer) {
+        fLayers.push(layer);
     }
 
     void onBackendCreated();
@@ -207,22 +175,7 @@ public:
 protected:
     Window();
 
-    OnBackendCreatedFunc   fBackendCreatedFunc;
-    void*                  fBackendCreatedUserData;
-    OnCharFunc             fCharFunc;
-    void*                  fCharUserData;
-    OnKeyFunc              fKeyFunc;
-    void*                  fKeyUserData;
-    OnMouseFunc            fMouseFunc;
-    void*                  fMouseUserData;
-    OnMouseWheelFunc       fMouseWheelFunc;
-    void*                  fMouseWheelUserData;
-    OnTouchFunc            fTouchFunc;
-    void*                  fTouchUserData;
-    OnUIStateChangedFunc   fUIStateChangedFunc;
-    void*                  fUIStateChangedUserData;
-    OnPaintFunc            fPaintFunc;
-    void*                  fPaintUserData;
+    SkTDArray<Layer*>      fLayers;
     DisplayParams          fRequestedDisplayParams;
 
     WindowContext* fWindowContext = nullptr;