Use intptr_t for onTouch argument.

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 1c798df399b7fecf9817a01fc157e477e28fcfb3..7ec8baae36b7ef04f5ae0f92b17711e066568fd0 100644
--- a/tools/viewer/sk_app/Window.cpp
+++ b/tools/viewer/sk_app/Window.cpp
@@ -27,7 +27,7 @@ static bool default_mouse_func(int x, int y, Window::InputState state, uint32_t
     return false;
 }
 
-static bool default_touch_func(int owner, Window::InputState state, float x, float y,
+static bool default_touch_func(intptr_t owner, Window::InputState state, float x, float y,
                                void* userData) {
     return false;
 }
@@ -62,7 +62,7 @@ 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) {
+bool Window::onTouch(intptr_t owner, InputState state, float x, float y) {
     return fTouchFunc(owner, state, x, y, fTouchUserData);
 }