Make scroll offset type of float in cc

cc/blink/web_layer_impl.cc

 // Copyright 2014 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/blink/web_layer_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event_impl.h"
 #include "base/lazy_instance.h"
 #include "base/strings/string_util.h"
 #include "base/threading/thread_checker.h"
 #include "cc/animation/animation.h"
 #include "cc/base/region.h"
 #include "cc/base/switches.h"
 #include "cc/blink/web_animation_impl.h"
 #include "cc/blink/web_blend_mode.h"
 #include "cc/blink/web_filter_operations_impl.h"
 #include "cc/blink/web_to_cc_animation_delegate_adapter.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_position_constraint.h"
 #include "cc/trees/layer_tree_host.h"
 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
 #include "third_party/WebKit/public/platform/WebFloatRect.h"
 #include "third_party/WebKit/public/platform/WebGraphicsLayerDebugInfo.h"
 #include "third_party/WebKit/public/platform/WebLayerClient.h"
 #include "third_party/WebKit/public/platform/WebLayerPositionConstraint.h"
 #include "third_party/WebKit/public/platform/WebLayerScrollClient.h"
 #include "third_party/WebKit/public/platform/WebSize.h"
 #include "third_party/skia/include/utils/SkMatrix44.h"
+#include "ui/gfx/geometry/vector2d_conversions.h"
 
 using cc::Animation;
 using cc::Layer;
 using blink::WebLayer;
 using blink::WebFloatPoint;
 using blink::WebVector;
 using blink::WebRect;
 using blink::WebSize;
 using blink::WebColor;
 using blink::WebFilterOperations;
@@ skipping 220 matching lines @@
 }
 
 bool WebLayerImpl::hasActiveAnimation() {
   return layer_->HasActiveAnimation();
 }
 
 void WebLayerImpl::setForceRenderSurface(bool force_render_surface) {
   layer_->SetForceRenderSurface(force_render_surface);
 }
 
+void WebLayerImpl::setScrollPositionFloat(
+    const std::pair<double, double>& position) {

[danakj, 2014/09/25 15:13:30]

are you allowed to use std::pair in the blink public API? i guess you'll sort
that out on that side of the fence

[Yufeng Shen (Slow to review), 2014/09/25 20:06:23]

right, it is suggested to use a new type WebDoublePoint.

I will sync this patch with the patch that adds this new type
to blink side.

+  layer_->SetScrollOffset(gfx::ScrollOffset(position.first, position.second));
+}
+
+std::pair<double, double> WebLayerImpl::scrollPositionFloat() const {
+  return std::pair<double, double>(layer_->scroll_offset().x(),
+                                   layer_->scroll_offset().y());
+}
+
 void WebLayerImpl::setScrollPosition(blink::WebPoint position) {
-  layer_->SetScrollOffset(gfx::Point(position).OffsetFromOrigin());
+  layer_->SetScrollOffset(gfx::ScrollOffset(position.x, position.y));
 }
 
 blink::WebPoint WebLayerImpl::scrollPosition() const {
-  return gfx::PointAtOffsetFromOrigin(layer_->scroll_offset());
+  return gfx::PointAtOffsetFromOrigin(
+      gfx::ToFlooredVector2d(layer_->scroll_offset()));
 }
 
 void WebLayerImpl::setScrollClipLayer(WebLayer* clip_layer) {
   if (!clip_layer) {
     layer_->SetScrollClipLayerId(Layer::INVALID_ID);
     return;
   }
   layer_->SetScrollClipLayerId(clip_layer->id());
 }
 
@@ skipping 184 matching lines @@
   if (parent)
     clip_parent = static_cast<WebLayerImpl*>(parent)->layer();
   layer_->SetClipParent(clip_parent);
 }
 
 Layer* WebLayerImpl::layer() const {
   return layer_.get();
 }
 
 }  // namespace cc_blink