clang/win: Let some chromium_code targets build with -Wextra.

content/browser/web_contents/aura/overscroll_window_delegate_unittest.cc

 // Copyright 2015 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/web_contents/aura/overscroll_window_delegate.h"
 
 #include "content/browser/renderer_host/overscroll_controller_delegate.h"
 #include "content/public/browser/overscroll_configuration.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/aura/test/aura_test_base.h"
@@ skipping 36 matching lines @@
 
   // Accessors.
   aura::Window* window() { return window_.get(); }
 
   bool overscroll_complete() { return overscroll_complete_; }
   bool overscroll_started() { return overscroll_started_; }
   bool mode_changed() { return mode_changed_; }
 
   OverscrollMode current_mode() { return current_mode_; }
 
-  const float touch_start_threshold() {
-    return touch_start_threshold_;
-  }
+  float touch_start_threshold() { return touch_start_threshold_; }
 
-  const float touch_complete_threshold() {
+  float touch_complete_threshold() {
     return kTestWindowWidth * touch_complete_threshold_;
   }
 
  protected:
   // aura::test::AuraTestBase:
   void SetUp() override {
     aura::test::AuraTestBase::SetUp();
     Reset();
     ui::GestureConfiguration::GetInstance()
         ->set_max_touch_move_in_pixels_for_click(0);
@@ skipping 172 matching lines @@
   EXPECT_EQ(current_mode(), OVERSCROLL_NONE);
   EXPECT_FALSE(overscroll_complete());
 
   // We should be able to restart the overscroll without lifting the finger.
   generator.MoveTouch(gfx::Point(touch_x + touch_start_threshold() + 1, 0));
   EXPECT_EQ(current_mode(), OVERSCROLL_EAST);
   EXPECT_FALSE(overscroll_complete());
 }
 
 }  // namespace content