cc: Always commit and redraw after scrolling

cc/layer_tree_host_impl_unittest.cc

 // Copyright 2011 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 "cc/layer_tree_host_impl.h"
 
 #include <cmath>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 500 matching lines @@
     // Scrolling to the right/bottom will succeed.
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(10, 0)));
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(0, 10)));
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(10, 10)));
 
     // Scrolling to left/top will now succeed.
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(-10, 0)));
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(0, -10)));
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(-10, -10)));
 
+    // Scrolling diagonally against an edge will succeed.
+    EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(10, -10)));
+    EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(-10, 0)));
+    EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(-10, 10)));
+
     // Trying to scroll more than the available space will also succeed.
     EXPECT_TRUE(m_hostImpl->scrollBy(gfx::Point(), gfx::Vector2d(5000, 5000)));
 }
 
 TEST_P(LayerTreeHostImplTest, maxScrollOffsetChangedByDeviceScaleFactor)
 {
     setupScrollAndContentsLayers(gfx::Size(100, 100));
 
     float deviceScaleFactor = 2;
     gfx::Size layoutViewport(25, 25);
@@ skipping 4359 matching lines @@
 {
     pinchZoomPanViewportAndScrollBoundaryTest(2);
 }
 
 INSTANTIATE_TEST_CASE_P(LayerTreeHostImplTests,
                         LayerTreeHostImplTest,
                         ::testing::Values(false, true));
 
 }  // namespace
 }  // namespace cc