CC: Fix call order of ScrollOffsetDelegate in ActivatePendingTree.

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 <cmath>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 192 matching lines @@
 
     for (size_t i = 0; i < scroll_info.scrolls.size(); ++i) {
       if (scroll_info.scrolls[i].layer_id != id)
         continue;
       times_encountered++;
     }
 
     ASSERT_EQ(0, times_encountered);
   }
 
-  LayerImpl* SetupScrollAndContentsLayers(gfx::Size content_size) {
+  LayerImpl* CreateScrollAndContentsLayers(LayerTreeImpl* layer_tree_impl,
+                                           gfx::Size content_size) {
     scoped_ptr<LayerImpl> root =
-        LayerImpl::Create(host_impl_->active_tree(), 1);
+        LayerImpl::Create(layer_tree_impl, 1);
     root->SetBounds(content_size);
     root->SetContentBounds(content_size);
     root->SetPosition(gfx::PointF());
     root->SetAnchorPoint(gfx::PointF());
 
     scoped_ptr<LayerImpl> scroll =
-        LayerImpl::Create(host_impl_->active_tree(), 2);
+        LayerImpl::Create(layer_tree_impl, 2);
     LayerImpl* scroll_layer = scroll.get();
     scroll->SetScrollable(true);
     scroll->SetScrollOffset(gfx::Vector2d());
     scroll->SetMaxScrollOffset(gfx::Vector2d(content_size.width(),
                                              content_size.height()));
     scroll->SetBounds(content_size);
     scroll->SetContentBounds(content_size);
     scroll->SetPosition(gfx::PointF());
     scroll->SetAnchorPoint(gfx::PointF());
 
     scoped_ptr<LayerImpl> contents =
-        LayerImpl::Create(host_impl_->active_tree(), 3);
+        LayerImpl::Create(layer_tree_impl, 3);
     contents->SetDrawsContent(true);
     contents->SetBounds(content_size);
     contents->SetContentBounds(content_size);
     contents->SetPosition(gfx::PointF());
     contents->SetAnchorPoint(gfx::PointF());
 
     scroll->AddChild(contents.Pass());
     root->AddChild(scroll.Pass());
 
-    host_impl_->active_tree()->SetRootLayer(root.Pass());
+    layer_tree_impl->SetRootLayer(root.Pass());
+    return scroll_layer;
+  }
+
+  LayerImpl* SetupScrollAndContentsLayers(gfx::Size content_size) {
+    LayerImpl* scroll_layer = CreateScrollAndContentsLayers(
+        host_impl_->active_tree(), content_size);
     host_impl_->active_tree()->DidBecomeActive();
     return scroll_layer;
   }
 
   scoped_ptr<LayerImpl> CreateScrollableLayer(int id, gfx::Size size) {
     scoped_ptr<LayerImpl> layer =
         LayerImpl::Create(host_impl_->active_tree(), id);
     layer->SetScrollable(true);
     layer->SetDrawsContent(true);
     layer->SetBounds(size);
@@ skipping 2249 matching lines @@
   EXPECT_EQ(current_offset + scroll_delta,
             scroll_delegate.last_set_scroll_offset());
 
   current_offset = gfx::Vector2dF(42.f, 41.f);
   scroll_delegate.set_getter_return_value(current_offset);
   host_impl_->ScrollBy(gfx::Point(), scroll_delta);
   EXPECT_EQ(current_offset + scroll_delta,
             scroll_delegate.last_set_scroll_offset());
   host_impl_->ScrollEnd();
 
+  // 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_->ActivatePendingTree();
+  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::Vector2dF(13.f, 12.f);
   scroll_delegate.set_getter_return_value(current_offset);
   host_impl_->SetRootLayerScrollOffsetDelegate(NULL);
 
   EXPECT_EQ(current_offset.ToString(),
             scroll_layer->TotalScrollOffset().ToString());
 }
 
@@ skipping 4250 matching lines @@
   host_impl_.reset();
 
   // The CopyOutputResult's callback was cancelled, the CopyOutputResult
   // released, and the texture deleted.
   EXPECT_TRUE(context_provider->HasOneRef());
   EXPECT_EQ(0u, context_provider->TestContext3d()->NumTextures());
 }
 
 }  // namespace
 }  // namespace cc