Fix precision problem in TouchActionBrowserTest.

content/browser/renderer_host/input/touch_action_browsertest.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 <limits>
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "content/browser/renderer_host/input/synthetic_gesture.h"
@@ skipping 142 matching lines @@
         base::Bind(&TouchActionBrowserTest::OnSyntheticGestureCompleted,
                    base::Unretained(this)));
 
     // Runs until we get the OnSyntheticGestureCompleted callback
     runner_->Run();
     runner_ = NULL;
 
     // Expect that the compositor scrolled at least one pixel while the
     // main thread was in a busy loop.
     while (wait_until_scrolled &&
-           frame_watcher->LastMetadata().root_scroll_offset.y() <
-               distance.y()) {
+            (frame_watcher->LastMetadata().root_scroll_offset.y() -
+                    distance.y()) > std::numeric_limits<double>::epsilon()) {

[aelias_OOO_until_Jul13, 2016/10/06 19:33:51]

This is the second time we've had precision problems with this test and
exactitude really does not matter.  The small epsilon risks not fully solving
the problem.  Please switch to
"frame_watcher->LastMetadata().root_scroll_offset.y() < distance.y() / 2"

[huapengl, 2016/10/07 16:59:40]

Done.

       frame_watcher->WaitFrames(1);
     }
 
     // Check the scroll offset
     int scrollTop = GetScrollTop();
     if (scrollTop == 0)
       return false;
 
     // Allow for 1px rounding inaccuracies for some screen sizes.
     EXPECT_NEAR(distance.y(), scrollTop, 1);

[aelias_OOO_until_Jul13, 2016/10/06 19:33:51]

Please replace this line by EXPECT_LT(distance.y() / 2, scrollTop)

[huapengl, 2016/10/07 16:59:40]

Done.

     return true;
   }
 
  private:
   scoped_refptr<MessageLoopRunner> runner_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchActionBrowserTest);
 };
 
 // Mac doesn't yet have a gesture recognizer, so can't support turning touch
@@ skipping 34 matching lines @@
       DoTouchScroll(gfx::Point(50, 150), gfx::Vector2d(0, 45), false);
   EXPECT_FALSE(scrolled);
 
   EXPECT_EQ(1, ExecuteScriptAndExtractInt("eventCounts.touchstart"));
   EXPECT_GE(ExecuteScriptAndExtractInt("eventCounts.touchmove"), 1);
   EXPECT_EQ(1, ExecuteScriptAndExtractInt("eventCounts.touchend"));
   EXPECT_EQ(0, ExecuteScriptAndExtractInt("eventCounts.touchcancel"));
 }
 
 }  // namespace content