Implement touch control

tools/viewer/sk_app/Window.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "Window.h"
 
 #include "SkSurface.h"
 #include "SkCanvas.h"
 #include "VulkanWindowContext.h"
 
 namespace sk_app {
 
 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_touch_func(int owner, Window::InputState state, float x, float y,
+                               void* userData) {
+    return false;
+}
+
 static void default_paint_func(SkCanvas*, void* userData) {}
 
 Window::Window() : fCharFunc(default_char_func)
                  , fKeyFunc(default_key_func)
                  , fMouseFunc(default_mouse_func)
+                 , fTouchFunc(default_touch_func)
                  , fPaintFunc(default_paint_func) {
 }
 
 void Window::detach() {
     delete fWindowContext;
     fWindowContext = nullptr;
 }
 
 bool Window::onChar(SkUnichar c, uint32_t modifiers) {
     return fCharFunc(c, modifiers, fCharUserData);
 }
 
 bool Window::onKey(Key key, InputState state, uint32_t modifiers) {
     return fKeyFunc(key, state, modifiers, fKeyUserData);
 }
 
 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) {
+    return fTouchFunc(owner, state, x, y, fTouchUserData);
+}
+
 void Window::onPaint() {
     SkSurface* backbuffer = fWindowContext->getBackbufferSurface();
     if (backbuffer) {
         // draw into the canvas of this surface
         SkCanvas* canvas = backbuffer->getCanvas();
 
         fPaintFunc(canvas, fPaintUserData);
 
         canvas->flush();
 
@@ skipping 12 matching lines @@
 
 const DisplayParams& Window::getDisplayParams() {
     return fWindowContext->getDisplayParams();
 }
 
 void Window::setDisplayParams(const DisplayParams& params) {
     fWindowContext->setDisplayParams(params);
 }
 
 }   // namespace sk_app