Fix recording of kAnimatingScrollOnMain

ui/events/blink/input_handler_proxy_unittest.cc

 // Copyright 2013 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 "ui/events/blink/input_handler_proxy.h"
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/test/histogram_tester.h"
@@ skipping 2762 matching lines @@
   testing::Mock::VerifyAndClearExpectations(&mock_client);
   testing::Mock::VerifyAndClearExpectations(&mock_synchronous_input_handler);
 }
 
 TEST_P(InputHandlerProxyTest, MainThreadScrollingMouseWheelHistograms) {
   input_handler_->RecordMainThreadScrollingReasonsForTest(
       blink::WebGestureDeviceTouchpad,
       cc::MainThreadScrollingReason::kHasBackgroundAttachmentFixedObjects |
           cc::MainThreadScrollingReason::kThreadedScrollingDisabled |
           cc::MainThreadScrollingReason::kPageOverlay |
           cc::MainThreadScrollingReason::kAnimatingScrollOnMainThread);

[tdresser, 2016/08/30 15:07:56]

Maybe add a comment to the test indicating why animating scroll on the main
thread is special? 

[Ian Vollick, 2016/08/30 17:55:06]

Done.

 
   EXPECT_THAT(
       histogram_tester().GetAllSamples("Renderer4.MainThreadWheelScrollReason"),
       testing::ElementsAre(base::Bucket(1, 1), base::Bucket(3, 1),
+                           base::Bucket(5, 1)));
+
+  input_handler_->RecordMainThreadScrollingReasonsForTest(
+      blink::WebGestureDeviceTouchpad,
+      cc::MainThreadScrollingReason::kAnimatingScrollOnMainThread);
+
+  EXPECT_THAT(
+      histogram_tester().GetAllSamples("Renderer4.MainThreadWheelScrollReason"),
+      testing::ElementsAre(base::Bucket(1, 1), base::Bucket(3, 1),
                            base::Bucket(5, 1), base::Bucket(14, 1)));
 }
 
 
 INSTANTIATE_TEST_CASE_P(AnimateInput,
                         InputHandlerProxyTest,
                         testing::ValuesIn(test_types));
 }  // namespace test
 }  // namespace ui