Move inval dedup to Window for wider usages.

tools/viewer/sk_app/android/Window_android.cpp

Index: tools/viewer/sk_app/android/Window_android.cpp
diff --git a/tools/viewer/sk_app/android/Window_android.cpp b/tools/viewer/sk_app/android/Window_android.cpp
index 106c40b7b0dd61a0ebf7b4203e525b72847cba44..ed03c814ddf7827448dee93bb6a69cb6b767fb4a 100644
--- a/tools/viewer/sk_app/android/Window_android.cpp
+++ b/tools/viewer/sk_app/android/Window_android.cpp
@@ -64,8 +64,16 @@ void Window_android::onDisplayDestroyed() {
     detach();
 }
 
-void Window_android::inval() {
-    fSkiaAndroidApp->inval();
+void Window_android::onInval() {
+    fSkiaAndroidApp->postMessage(Message(kContentInvalidated));
+}
+
+void Window_android::paintIfNeeded() {
+    if (fWindowContext) { // Check if initDisplay has already been called
+        onPaint();
+    } else {
+        markInvalProcessed();
+    }
 }
 
 }   // namespace sk_app