Implement touch control

tools/viewer/sk_app/Window.cpp

Index: tools/viewer/sk_app/Window.cpp
diff --git a/tools/viewer/sk_app/Window.cpp b/tools/viewer/sk_app/Window.cpp
index 47053be5afc5a503f398316238bdda317fd94ead..4f21bffccb4ea7b790095755a30ad93d0e4207b8 100644
--- a/tools/viewer/sk_app/Window.cpp
+++ b/tools/viewer/sk_app/Window.cpp
@@ -52,6 +52,26 @@ bool Window::onMouse(int x, int y, InputState state, uint32_t modifiers) {
     return fMouseFunc(x, y, state, modifiers, fMouseUserData);
 }
 
+bool Window::onTouch(int owner, InputState state, float x, float y) {
+    void* castedOwner = reinterpret_cast<void*>(owner);
+    switch (state) {
+        case Window::kUp_InputState: {
+            fGesture.touchEnd(castedOwner);
+            break;
+        }
+        case Window::kDown_InputState: {
+            fGesture.touchBegin(castedOwner, x, y);
+            break;
+        }
+        case Window::kMove_InputState: {
+            fGesture.touchMoved(castedOwner, x, y);
+            break;
+        }
+    }
+    inval();
+    return true;
+}
+
 void Window::onPaint() {
     SkSurface* backbuffer = fWindowContext->getBackbufferSurface();
     if (backbuffer) {
@@ -83,4 +103,12 @@ void Window::setDisplayParams(const DisplayParams& params) {
     fWindowContext->setDisplayParams(params);
 }
 
+const SkMatrix& Window::getGestureLocalM() {
+    return fGesture.localM();
+}
+
+const SkMatrix& Window::getGestureGlobalM() const {
+    return fGesture.globalM();
+}
+
 }   // namespace sk_app