Merge r183887 - RenderLayer::currentTransform computes a pixel snappe…

…d rect it doesn't use.

https://bugs.webkit.org/show_bug.cgi?id=144708

Reviewed by Simon Fraser.

* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::currentTransform):

Only compute a pixel snapped rect if we actually end up needing it. The common case
is that this rect is not needed, so pushing it inside the two if statements
speeds up the common case.

Source/WebCore/ChangeLog

@@ -1,3 +1,17 @@
+2015-05-06  David Hyatt  <hyatt@apple.com>
+
+        RenderLayer::currentTransform computes a pixel snapped rect it doesn't use.
+        https://bugs.webkit.org/show_bug.cgi?id=144708
+
+        Reviewed by Simon Fraser.
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::RenderLayer::currentTransform):
+
+        Only compute a pixel snapped rect if we actually end up needing it. The common case
+        is that this rect is not needed, so pushing it inside the two if statements
+        speeds up the common case.
+
 2015-05-06  David Hyatt  <hyatt@apple.com>
 
         Optimize topLeftLocationOffset() addition in updateLayerPosition

Source/WebCore/rendering/RenderLayer.cpp

@@ -971,12 +971,12 @@ TransformationMatrix RenderLayer::currentTransform(RenderStyle::ApplyTransformOr
 {
     if (!m_transform)
         return TransformationMatrix();
-
+    
     RenderBox* box = renderBox();
     ASSERT(box);
-    FloatRect pixelSnappedBorderRect = snapRectToDevicePixels(box->borderBoxRect(), box->document().deviceScaleFactor());
     if (renderer().style().isRunningAcceleratedAnimation()) {
         TransformationMatrix currTransform;
+        FloatRect pixelSnappedBorderRect = snapRectToDevicePixels(box->borderBoxRect(), box->document().deviceScaleFactor());
         RefPtr<RenderStyle> style = renderer().animation().getAnimatedStyleForRenderer(renderer());
         style->applyTransform(currTransform, pixelSnappedBorderRect, applyOrigin);
         makeMatrixRenderable(currTransform, canRender3DTransforms());
@@ -986,6 +986,7 @@ TransformationMatrix RenderLayer::currentTransform(RenderStyle::ApplyTransformOr
     // m_transform includes transform-origin, so we need to recompute the transform here.
     if (applyOrigin == RenderStyle::ExcludeTransformOrigin) {
         TransformationMatrix currTransform;
+        FloatRect pixelSnappedBorderRect = snapRectToDevicePixels(box->borderBoxRect(), box->document().deviceScaleFactor());
         box->style().applyTransform(currTransform, pixelSnappedBorderRect, RenderStyle::ExcludeTransformOrigin);
         makeMatrixRenderable(currTransform, canRender3DTransforms());
         return currTransform;