Refactor delegated scrolling in LayerImpl

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 3954 matching lines @@
   host_impl_->PinchGestureEnd();
   host_impl_->ScrollEnd();
 
   // Scrolling should be relative to the offset as returned by the delegate.
   gfx::Vector2dF scroll_delta(0.f, 10.f);
   gfx::ScrollOffset current_offset(7.f, 8.f);
 
   scroll_delegate.set_getter_return_value(current_offset);
   EXPECT_EQ(InputHandler::SCROLL_STARTED,
             host_impl_->ScrollBegin(gfx::Point(), InputHandler::GESTURE));
+  host_impl_->OnRootLayerDelegatedScrollOffsetChanged();
 
   host_impl_->ScrollBy(gfx::Point(), scroll_delta);
   EXPECT_EQ(ScrollOffsetWithDelta(current_offset, scroll_delta),
             scroll_delegate.last_set_scroll_offset());
 
   current_offset = gfx::ScrollOffset(42.f, 41.f);
   scroll_delegate.set_getter_return_value(current_offset);
+  host_impl_->OnRootLayerDelegatedScrollOffsetChanged();
   host_impl_->ScrollBy(gfx::Point(), scroll_delta);
   EXPECT_EQ(current_offset + gfx::ScrollOffset(scroll_delta),
             scroll_delegate.last_set_scroll_offset());
   host_impl_->ScrollEnd();
   scroll_delegate.set_getter_return_value(gfx::ScrollOffset());
+  host_impl_->OnRootLayerDelegatedScrollOffsetChanged();
 
   // Forces a full tree synchronization and ensures that the scroll delegate
   // sees the correct size of the new tree.
   gfx::Size new_size(42, 24);
   host_impl_->CreatePendingTree();
   CreateScrollAndContentsLayers(host_impl_->pending_tree(), new_size);
   host_impl_->ActivateSyncTree();
   EXPECT_EQ(new_size, scroll_delegate.scrollable_size());
 
   // Un-setting the delegate should propagate the delegate's current offset to
   // the root scrollable layer.
   current_offset = gfx::ScrollOffset(13.f, 12.f);
   scroll_delegate.set_getter_return_value(current_offset);
+  host_impl_->OnRootLayerDelegatedScrollOffsetChanged();
   host_impl_->SetRootLayerScrollOffsetDelegate(NULL);
 
   EXPECT_EQ(current_offset.ToString(),
             scroll_layer->CurrentScrollOffset().ToString());
 }
 
 void CheckLayerScrollDelta(LayerImpl* layer, gfx::Vector2dF scroll_delta) {
   const gfx::Transform target_space_transform =
       layer->draw_properties().target_space_transform;
   EXPECT_TRUE(target_space_transform.IsScaleOrTranslation());
@@ skipping 4455 matching lines @@
   // surface.
   EXPECT_EQ(0, num_lost_surfaces_);
   host_impl_->DidLoseOutputSurface();
   EXPECT_EQ(1, num_lost_surfaces_);
   host_impl_->DidLoseOutputSurface();
   EXPECT_LE(1, num_lost_surfaces_);
 }
 
 }  // namespace
 }  // namespace cc