Move inval dedup to Window for wider usages.

tools/viewer/sk_app/CommandSet.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 "CommandSet.h"
 
 #include "SkCanvas.h"
@@ skipping 19 matching lines @@
             case kNone_HelpMode:
                 this->fHelpMode = kGrouped_HelpMode;
                 break;
             case kGrouped_HelpMode:
                 this->fHelpMode = kAlphabetical_HelpMode;
                 break;
             case kAlphabetical_HelpMode:
                 this->fHelpMode = kNone_HelpMode;
                 break;
         }
-        fWindow->inval();
+        fWindow->checkAndInval();
     });
 }
 
 void CommandSet::attach(Window* window) {
     fWindow = window;
     window->registerKeyFunc(on_key_handler, this);
     window->registerCharFunc(on_char_handler, this);
 }
 
 bool CommandSet::onKey(Window::Key key, Window::InputState state, uint32_t modifiers) {
@@ skipping 97 matching lines @@
         }
 
         canvas->drawText(cmd.fKeyName.c_str(), cmd.fKeyName.size(), x, y, paint);
         SkString text = SkStringPrintf(": %s", cmd.fDescription.c_str());
         canvas->drawText(text.c_str(), text.size(), x + keyWidth, y, paint);
         y += paint.getTextSize() + 2;
     }
 }
 
 }   // namespace sk_app