Use a minimum touch size for selection handle hit testing

content/browser/renderer_host/input/touch_handle_unittest.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 "content/browser/renderer_host/input/touch_handle.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/test/mock_motion_event.h"
 #include "ui/gfx/geometry/rect_f.h"
 
@@ skipping 406 matching lines @@
   EXPECT_FALSE(handle.WillHandleTouchEvent(event));
   EXPECT_FALSE(IsDragging());
 
   event.SetTouchMajor(kTouchSize);
   EXPECT_TRUE(handle.WillHandleTouchEvent(event));
   EXPECT_TRUE(IsDragging());
 
   event.SetTouchMajor(kTouchSize * 2.f);
   EXPECT_TRUE(handle.WillHandleTouchEvent(event));
   EXPECT_TRUE(IsDragging());
+
+  // Ensure a touch size of 0 can still register a hit.
+  event = MockMotionEvent(MockMotionEvent::ACTION_DOWN,
+                          event_time,
+                          kDefaultDrawableSize / 2.f,
+                          kDefaultDrawableSize / 2.f);
+  event.SetTouchMajor(0);
+  EXPECT_TRUE(handle.WillHandleTouchEvent(event));
+  EXPECT_TRUE(IsDragging());
 }
 
 TEST_F(TouchHandleTest, Tap) {
   TouchHandle handle(this, TOUCH_HANDLE_CENTER);
   handle.SetVisible(true, TouchHandle::ANIMATION_NONE);
 
   base::TimeTicks event_time = base::TimeTicks::Now();
 
   // ACTION_CANCEL shouldn't trigger a tap.
   MockMotionEvent event(MockMotionEvent::ACTION_DOWN, event_time, 0, 0);
@@ skipping 14 matching lines @@
   // Only a brief tap should trigger a tap.
   event = MockMotionEvent(MockMotionEvent::ACTION_DOWN, event_time, 0, 0);
   EXPECT_TRUE(handle.WillHandleTouchEvent(event));
   event_time += base::TimeDelta::FromMilliseconds(50);
   event = MockMotionEvent(MockMotionEvent::ACTION_UP, event_time, 0, 0);
   EXPECT_TRUE(handle.WillHandleTouchEvent(event));
   EXPECT_TRUE(GetAndResetHandleTapped());
 }
 
 }  // namespace content