Move inval dedup to Window for wider usages.

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"
@@ skipping 45 matching lines @@
 
 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() {
+    SkAutoMutexAcquire ama(fMutex);

[jvanverth1, 2016/05/23 14:22:32]

How long does the mutex take? On single-threaded systems we'd want to run as
fast as possible. Maybe place in SKIA_BUILD_ANDROID block?

+    fIsContentInvalidated = false;

[djsollen, 2016/05/23 14:44:26]

putting this here won't work on Android as the inval message calls
paintIfNeeded() which checks the status of the backing window before getting
here.  So you could end up in a situation like...

1) post inval message
2) receive inval but don't call onPaint b/c the surface is not ready
3) all subsequent attempts to inval will be ignored
4) nothing ever draws. :(

[liyuqian, 2016/05/23 14:58:24]

Good catch! Revised.

     sk_sp<SkSurface> backbuffer = fWindowContext->getBackbufferSurface();
     if (backbuffer) {
         // draw into the canvas of this surface
         SkCanvas* canvas = backbuffer->getCanvas();
 
         fPaintFunc(canvas, fPaintUserData);
 
         canvas->flush();
 
         fWindowContext->swapBuffers();
     } else {
         // try recreating testcontext
     }
 }
 
 void Window::onResize(uint32_t w, uint32_t h) {
     fWidth = w;
     fHeight = h;
     fWindowContext->resize(w, h);
 }
 
 const DisplayParams& Window::getDisplayParams() {
     return fWindowContext->getDisplayParams();
 }
 
 void Window::setDisplayParams(const DisplayParams& params) {
     fWindowContext->setDisplayParams(params);
 }
 
+void Window::checkAndInval() {
+    SkAutoMutexAcquire ama(fMutex);
+    if (!fIsContentInvalidated) {
+        fIsContentInvalidated = true;
+        inval();
+    }
+}
+
 }   // namespace sk_app