Make scroll offset type of float in cc

cc/trees/layer_tree_host.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.h"
 
 #include <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 22 matching lines @@
 #include "cc/resources/prioritized_resource_manager.h"
 #include "cc/resources/ui_resource_request.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_host_impl.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/occlusion_tracker.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/thread_proxy.h"
 #include "cc/trees/tree_synchronizer.h"
+#include "ui/gfx/geometry/vector2d_conversions.h"

[danakj, 2014/09/27 00:00:44]

unused?

[Yufeng Shen (Slow to review), 2014/09/29 19:27:33]

Done.

 #include "ui/gfx/size_conversions.h"
 
 namespace {
 static base::StaticAtomicSequenceNumber s_layer_tree_host_sequence_number;
 }
 
 namespace cc {
 
 RendererCapabilities::RendererCapabilities(ResourceFormat best_texture_format,
                                            bool allow_partial_texture_updates,
@@ skipping 1019 matching lines @@
   for (size_t i = 0; i < info->scrolls.size(); ++i) {
     Layer* layer = LayerTreeHostCommon::FindLayerInSubtree(
         root_layer_.get(), info->scrolls[i].layer_id);
     if (!layer)
       continue;
     if (layer == outer_viewport_scroll_layer_.get()) {
       outer_viewport_scroll_delta += info->scrolls[i].scroll_delta;
     } else if (layer == inner_viewport_scroll_layer_.get()) {
       inner_viewport_scroll_delta += info->scrolls[i].scroll_delta;
     } else {
-      layer->SetScrollOffsetFromImplSide(layer->scroll_offset() +
-                                         info->scrolls[i].scroll_delta);
+      layer->SetScrollOffsetFromImplSide(
+          layer->scroll_offset() +

[danakj, 2014/09/27 00:00:44]

ScrollOffsetWithDelta

[Yufeng Shen (Slow to review), 2014/09/29 19:27:33]

Done.

+          gfx::ScrollOffset(info->scrolls[i].scroll_delta));
     }
   }
 
   if (!inner_viewport_scroll_delta.IsZero() ||
       !outer_viewport_scroll_delta.IsZero() ||
       info->page_scale_delta != 1.f ||
       info->top_controls_delta) {
     // SetScrollOffsetFromImplSide above could have destroyed the tree,
     // so re-get this layer before doing anything to it.
 
     // Preemptively apply the scroll offset and scale delta here before sending
     // it to the client.  If the client comes back and sets it to the same
     // value, then the layer can early out without needing a full commit.
     DCHECK(inner_viewport_scroll_layer_.get());  // We should always have this.
 
     inner_viewport_scroll_layer_->SetScrollOffsetFromImplSide(
-        inner_viewport_scroll_layer_->scroll_offset() +
-        inner_viewport_scroll_delta);
+        gfx::ScrollOffsetWithDelta(
+            inner_viewport_scroll_layer_->scroll_offset(),
+            inner_viewport_scroll_delta));
     if (outer_viewport_scroll_layer_.get()) {
       outer_viewport_scroll_layer_->SetScrollOffsetFromImplSide(
-          outer_viewport_scroll_layer_->scroll_offset() +
-          outer_viewport_scroll_delta);
+          gfx::ScrollOffsetWithDelta(
+              outer_viewport_scroll_layer_->scroll_offset(),
+              outer_viewport_scroll_delta));
     }
     ApplyPageScaleDeltaFromImplSide(info->page_scale_delta);
 
     client_->ApplyViewportDeltas(
         inner_viewport_scroll_delta + outer_viewport_scroll_delta,
         info->page_scale_delta,
         info->top_controls_delta);
   }
 }
 
@@ skipping 201 matching lines @@
   swap_promise_list_.push_back(swap_promise.Pass());
 }
 
 void LayerTreeHost::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
   for (size_t i = 0; i < swap_promise_list_.size(); i++)
     swap_promise_list_[i]->DidNotSwap(reason);
   swap_promise_list_.clear();
 }
 
 }  // namespace cc