Improve test coverage of unused scroll delta for cc scrolling.

cc/trees/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/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/bind.h"
@@ skipping 7000 matching lines @@
 
 TEST_F(LayerTreeHostImplWithTopControlsTest, TopControlsAnimationScheduling) {
   SetupScrollAndContentsLayers(gfx::Size(100, 100))
       ->PushScrollOffsetFromMainThread(gfx::ScrollOffset(0, 10));
   host_impl_->DidChangeTopControlsPosition();
   EXPECT_TRUE(did_request_animate_);
   EXPECT_TRUE(did_request_redraw_);
 }
 
 TEST_F(LayerTreeHostImplWithTopControlsTest, ScrollHandledByTopControls) {
+  InputHandlerScrollResult result;
   LayerImpl* scroll_layer = SetupScrollAndContentsLayers(gfx::Size(100, 200));
   host_impl_->SetViewportSize(gfx::Size(100, 100));
   host_impl_->top_controls_manager()->UpdateTopControlsState(
       BOTH, SHOWN, false);
   DrawFrame();
 
   EXPECT_EQ(InputHandler::SCROLL_STARTED,
             host_impl_->ScrollBegin(gfx::Point(), InputHandler::GESTURE));
   EXPECT_EQ(0, host_impl_->top_controls_manager()->ControlsTopOffset());
   EXPECT_EQ(gfx::Vector2dF().ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 
   // Scroll just the top controls and verify that the scroll succeeds.
   const float residue = 10;
   float offset = top_controls_height_ - residue;
-  EXPECT_TRUE(
-      host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset)).did_scroll);
+  result = host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset));
+  EXPECT_EQ(result.unused_scroll_delta, gfx::Vector2d(0, 0));
+  EXPECT_TRUE(result.did_scroll);
   EXPECT_FLOAT_EQ(-offset,
                   host_impl_->top_controls_manager()->ControlsTopOffset());
   EXPECT_EQ(gfx::Vector2dF().ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 
   // Scroll across the boundary
   const float content_scroll = 20;
   offset = residue + content_scroll;
-  EXPECT_TRUE(
-      host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset)).did_scroll);
+  result = host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset));
+  EXPECT_TRUE(result.did_scroll);
+  EXPECT_EQ(result.unused_scroll_delta, gfx::Vector2d(0, 0));
   EXPECT_EQ(-top_controls_height_,
             host_impl_->top_controls_manager()->ControlsTopOffset());
   EXPECT_EQ(gfx::Vector2dF(0, content_scroll).ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 
   // Now scroll back to the top of the content
   offset = -content_scroll;
-  EXPECT_TRUE(
-      host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset)).did_scroll);
+  result = host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset));
+  EXPECT_TRUE(result.did_scroll);
+  EXPECT_EQ(result.unused_scroll_delta, gfx::Vector2d(0, 0));
   EXPECT_EQ(-top_controls_height_,
             host_impl_->top_controls_manager()->ControlsTopOffset());
   EXPECT_EQ(gfx::Vector2dF().ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 
   // And scroll the top controls completely into view
   offset = -top_controls_height_;
-  EXPECT_TRUE(
-      host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset)).did_scroll);
+  result = host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset));
+  EXPECT_TRUE(result.did_scroll);
+  EXPECT_EQ(result.unused_scroll_delta, gfx::Vector2d(0, 0));
   EXPECT_EQ(0, host_impl_->top_controls_manager()->ControlsTopOffset());
   EXPECT_EQ(gfx::Vector2dF().ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 
   // And attempt to scroll past the end
-  EXPECT_FALSE(
-      host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset)).did_scroll);
+  result = host_impl_->ScrollBy(gfx::Point(), gfx::Vector2d(0, offset));
+  EXPECT_FALSE(result.did_scroll);
+  EXPECT_EQ(result.unused_scroll_delta, gfx::Vector2d(0, -50));
   EXPECT_EQ(0, host_impl_->top_controls_manager()->ControlsTopOffset());
   EXPECT_EQ(gfx::Vector2dF().ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 
   host_impl_->ScrollEnd();
 }
 
 TEST_F(LayerTreeHostImplWithTopControlsTest, TopControlsAnimationAtOrigin) {
   LayerImpl* scroll_layer = SetupScrollAndContentsLayers(gfx::Size(100, 200));
   host_impl_->SetViewportSize(gfx::Size(100, 200));
@@ skipping 1110 matching lines @@
   // Hold an unowned pointer to the output surface to use for mock expectations.
   MockReclaimResourcesOutputSurface* mock_output_surface = output_surface.get();
 
   CreateHostImpl(DefaultSettings(), output_surface.Pass());
   EXPECT_CALL(*mock_output_surface, ForceReclaimResources()).Times(1);
   host_impl_->BeginCommit();
 }
 
 }  // namespace
 }  // namespace cc