Remove page IDs from three WebContentsObserver APIs that don't need it.

apps/app_window.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "apps/app_window.h"
 
 #include <algorithm>
 
 #include "apps/app_window_geometry_cache.h"
 #include "apps/app_window_registry.h"
@@ skipping 463 matching lines @@
 }
 
 bool AppWindow::PreHandleGestureEvent(WebContents* source,
                                       const blink::WebGestureEvent& event) {
   // Disable pinch zooming in app windows.
   return event.type == blink::WebGestureEvent::GesturePinchBegin ||
          event.type == blink::WebGestureEvent::GesturePinchUpdate ||
          event.type == blink::WebGestureEvent::GesturePinchEnd;
 }
 
-void AppWindow::DidFirstVisuallyNonEmptyPaint(int32 page_id) {
+void AppWindow::DidFirstVisuallyNonEmptyPaint() {
   first_paint_complete_ = true;
   if (show_on_first_paint_) {
     DCHECK(delayed_show_type_ == SHOW_ACTIVE ||
            delayed_show_type_ == SHOW_INACTIVE);
     Show(delayed_show_type_);
   }
 }
 
 void AppWindow::OnNativeClose() {
   AppWindowRegistry::Get(browser_context_)->RemoveAppWindow(this);
@@ skipping 630 matching lines @@
         region.bounds.x(),
         region.bounds.y(),
         region.bounds.right(),
         region.bounds.bottom(),
         region.draggable ? SkRegion::kUnion_Op : SkRegion::kDifference_Op);
   }
   return sk_region;
 }
 
 }  // namespace apps