Move inval dedup to Window for wider usages.

tools/viewer/sk_app/Window.h

 /*
 * 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_DEFINED
 #define Window_DEFINED
 
 #include "DisplayParams.h"
 #include "SkRect.h"
 #include "SkTouchGesture.h"
 #include "SkTypes.h"
+#include "../private/SkMutex.h"
 
 class SkCanvas;
 
 namespace sk_app {
 
 class WindowContext;
 
 class Window {
 public:
     static Window* CreateNativeWindow(void* platformData);
 
     virtual ~Window() {};
 
     virtual void setTitle(const char*) = 0;
     virtual void show() = 0;
+
+    // Make sure that either onPaint or uncheckInval is called in the subclasses' implementations
+    // of inval. They unset fIsContentInvalided which allow checkAndInval to invalidate the content
+    // in the future.
     virtual void inval() = 0;

[djsollen, 2016/05/23 15:22:42]

make this protected

[liyuqian, 2016/05/23 15:49:25]

Done.

 
+    // Check if the current window has any pending inval; call inval if not.
+    void checkAndInval();
+    // Uncheck fIsContentInvalided to allow future checkAndInval to push inval events.
+    void uncheckInval();

[djsollen, 2016/05/23 15:22:42]

make this protected. I also find this naming confusing.  How about...

public:
  void inval();
protected:
  virtual void onInval() = 0;
  void markInvalReceived();

[liyuqian, 2016/05/23 15:49:25]

I don't want to change inval's name because it's implemented in many places and
let it be the name for another purpose is very confusing... Maybe renaming
checkAndInval to invalIfNeeded and putting inval in protected is clear enough?

Also, I'd prefer markInvalProcessed and make it public because other classes
have to call it.

+
     virtual bool scaleContentToFit() const { return false; }
     virtual bool supportsContentRect() const { return false; }
     virtual SkRect getContentRect() { return SkRect::MakeEmpty(); }
 
     enum BackendType {
         kNativeGL_BackendType,
         kVulkan_BackendType,
 
         kLast_BackendType = kVulkan_BackendType
     };
@@ skipping 115 matching lines @@
     OnKeyFunc    fKeyFunc;
     void*        fKeyUserData;
     OnMouseFunc  fMouseFunc;
     void*        fMouseUserData;
     OnTouchFunc  fTouchFunc;
     void*        fTouchUserData;
     OnPaintFunc  fPaintFunc;
     void*        fPaintUserData;
 
     WindowContext* fWindowContext = nullptr;
+
+    bool fIsContentInvalidated = false;  // use this to avoid duplicate invalidate events
 };
 
 }   // namespace sk_app
 #endif