ui: Make gfx::Size::Scale() mutate the class. Add gfx::ScaleSize() similar to Rect/Point.

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index c9c0820218f08db66d8956e3614006a376aef2fe..4739e9aa36a162bddbfe77b07101393800564c1c 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -100,12 +100,9 @@ bool PinchZoomViewport::setPageScaleFactorAndLimits(float pageScaleFactor, float
 
 gfx::RectF PinchZoomViewport::bounds() const
 {
-    gfx::SizeF scaledViewportSize = m_layoutViewportSize;
-    scaledViewportSize = scaledViewportSize.Scale(1 / totalPageScaleFactor());
-
-    gfx::RectF bounds(gfx::PointF(), scaledViewportSize);
+    gfx::RectF bounds(gfx::PointF(), m_layoutViewportSize);
+    bounds.Scale(1 / totalPageScaleFactor());
     bounds.Offset(m_pinchViewportScrollDelta);
-
     return bounds;
 }
 
@@ -302,7 +299,7 @@ void LayerTreeHostImpl::startPageScaleAnimation(gfx::Vector2d targetOffset, bool
     gfx::Vector2dF scrollTotal = m_rootScrollLayerImpl->scrollOffset() + m_rootScrollLayerImpl->scrollDelta();
     scrollTotal.Scale(m_pinchZoomViewport.pageScaleDelta());
     float scaleTotal = m_pinchZoomViewport.totalPageScaleFactor();
-    gfx::Size scaledContentSize = gfx::ToFlooredSize(contentSize().Scale(m_pinchZoomViewport.pageScaleDelta()));
+    gfx::Size scaledContentSize = gfx::ToFlooredSize(gfx::ScaleSize(contentSize(), m_pinchZoomViewport.pageScaleDelta()));
 
     double startTimeSeconds = (startTime - base::TimeTicks()).InSecondsF();
     m_pageScaleAnimation = PageScaleAnimation::create(gfx::ToFlooredVector2d(scrollTotal), scaleTotal, m_deviceViewportSize, scaledContentSize, startTimeSeconds);
@@ -981,10 +978,8 @@ void LayerTreeHostImpl::updateMaxScrollOffset()
     gfx::SizeF viewBounds = m_deviceViewportSize;
     if (LayerImpl* clipLayer = m_rootScrollLayerImpl->parent()) {
         // Compensate for non-overlay scrollbars.
-        if (clipLayer->masksToBounds()) {
-            viewBounds = clipLayer->bounds();
-            viewBounds = viewBounds.Scale(m_deviceScaleFactor);
-        }
+        if (clipLayer->masksToBounds())
+            viewBounds = gfx::ScaleSize(clipLayer->bounds(), m_deviceScaleFactor);
     }
 
     gfx::Size contentBounds = contentSize();
@@ -996,7 +991,7 @@ void LayerTreeHostImpl::updateMaxScrollOffset()
         contentBounds.set_width(contentBounds.width() / pageScaleFactor);
         contentBounds.set_height(contentBounds.height() / pageScaleFactor);
     } else {
-        viewBounds = viewBounds.Scale(1 / m_pinchZoomViewport.pageScaleDelta());
+        viewBounds.Scale(1 / m_pinchZoomViewport.pageScaleDelta());
     }
 
     gfx::Vector2dF maxScroll = BottomRight(gfx::Rect(contentBounds)) - BottomRight(gfx::RectF(viewBounds));
@@ -1286,7 +1281,7 @@ void LayerTreeHostImpl::computePinchZoomDeltas(ScrollAndScaleSet* scrollInfo)
     scrollBegin.Scale(m_pinchZoomViewport.pageScaleDelta());
     float scaleBegin = m_pinchZoomViewport.totalPageScaleFactor();
     float pageScaleDeltaToSend = m_pinchZoomViewport.minPageScaleFactor() / m_pinchZoomViewport.pageScaleFactor();
-    gfx::SizeF scaledContentsSize = contentSize().Scale(pageScaleDeltaToSend);
+    gfx::SizeF scaledContentsSize = gfx::ScaleSize(contentSize(), pageScaleDeltaToSend);
 
     gfx::Vector2d anchorOffset = m_previousPinchAnchor.OffsetFromOrigin();
     gfx::Vector2dF scrollEnd = scrollBegin + anchorOffset;