OverscrollController consumes scroll updates only during gesture-nav.

content/browser/renderer_host/render_widget_host_view_aura_unittest.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/memory/shared_memory.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 105 matching lines @@
     completed_mode_ = OVERSCROLL_NONE;
     delta_x_ = delta_y_ = 0.f;
   }
 
  private:
   // Overridden from OverscrollControllerDelegate:
   virtual gfx::Rect GetVisibleBounds() const OVERRIDE {
     return view_->IsShowing() ? view_->GetViewBounds() : gfx::Rect();
   }
 
-  virtual void OnOverscrollUpdate(float delta_x, float delta_y) OVERRIDE {
+  virtual bool OnOverscrollUpdate(float delta_x, float delta_y) OVERRIDE {
     delta_x_ = delta_x;
     delta_y_ = delta_y;
+    return true;
   }
 
   virtual void OnOverscrollComplete(OverscrollMode overscroll_mode) OVERRIDE {
     EXPECT_EQ(current_mode_, overscroll_mode);
     completed_mode_ = overscroll_mode;
     current_mode_ = OVERSCROLL_NONE;
   }
 
   virtual void OnOverscrollModeChange(OverscrollMode old_mode,
                                       OverscrollMode new_mode) OVERRIDE {
@@ skipping 2578 matching lines @@
   EXPECT_EQ(OVERSCROLL_NONE, overscroll_delegate()->completed_mode());
 
   SimulateGestureEvent(WebInputEvent::GestureScrollEnd,
                        blink::WebGestureDeviceTouchscreen);
   EXPECT_EQ(OVERSCROLL_NONE, overscroll_delegate()->current_mode());
   EXPECT_EQ(OVERSCROLL_EAST, overscroll_delegate()->completed_mode());
   EXPECT_EQ(3U, sink_->message_count());
 }
 
 }  // namespace content