Stub in Mac viewer code.

tools/viewer/sk_app/mac/Window_mac.h

Index: tools/viewer/sk_app/mac/Window_mac.h
diff --git a/tools/viewer/sk_app/mac/Window_mac.h b/tools/viewer/sk_app/mac/Window_mac.h
new file mode 100644
index 0000000000000000000000000000000000000000..016b13446573a5524acb060c330c51dc0939275b
--- /dev/null
+++ b/tools/viewer/sk_app/mac/Window_mac.h
@@ -0,0 +1,67 @@
+/*
+* Copyright 2016 Google Inc.
+*
+* Use of this source code is governed by a BSD-style license that can be
+* found in the LICENSE file.
+*/
+
+#ifndef Window_mac_DEFINED
+#define Window_mac_DEFINED
+
+#include "../Window.h"
+#include "SkChecksum.h"
+#include "SkTDynamicHash.h"
+
+namespace sk_app {
+
+struct ContextPlatformData_mac {
+#if 0
+    // TODO: use Mac-specific objects
+    Display*     fDisplay;
+    XWindow      fWindow;
+    XVisualInfo* fVisualInfo;
+#endif
+};
+
+class Window_mac : public Window {
+public:
+    Window_mac() : Window()
+#if 0
+                  // TODO: use Mac-specific objects
+                  , fDisplay(nullptr)
+                  , fWindow(0)
+                  , fGC(nullptr)
+                  , fVisualInfo(nullptr)
+#endif
+                  , fMSAASampleCount(0) {}
+    ~Window_mac() override { this->closeWindow(); }
+
+#if 0
+    // TODO: need to init with Mac-specific data
+    bool initWindow(Display* display, const DisplayParams* params);
+#endif
+
+    void setTitle(const char*) override;
+    void show() override;
+
+    bool attach(BackendType attachType, const DisplayParams& params) override;
+
+    void onInval() override;
+
+private:
+    void closeWindow();
+
+#if 0
+    // TODO: use Mac-specific window data
+    Display*     fDisplay;
+    XWindow      fWindow;
+    GC           fGC;
+    XVisualInfo* fVisualInfo;
+#endif
+    
+    int          fMSAASampleCount;
+};
+
+}   // namespace sk_app
+
+#endif