Bug 1205511 - Use nsPresContext::DevToCSSPixelScale() where appropriate. r=kats

--HG--
extra : source : 16ed1b039eb1522f555c35e9df6e5632c69ff0a4

dom/base/nsDocument.cpp

@@ -7838,9 +7838,7 @@ nsDocument::GetViewportInfo(const ScreenIntSize& aDisplaySize)
   // pixel an integer, and we want the adjusted value.
   float fullZoom = context ? context->DeviceContext()->GetFullZoom() : 1.0;
   fullZoom = (fullZoom == 0.0) ? 1.0 : fullZoom;
-  CSSToLayoutDeviceScale layoutDeviceScale(
-    (float)nsPresContext::AppUnitsPerCSSPixel() /
-    context->AppUnitsPerDevPixel());
+  CSSToLayoutDeviceScale layoutDeviceScale = context->CSSToDevPixelScale();
 
   CSSToScreenScale defaultScale = layoutDeviceScale
                                 * LayoutDeviceToScreenScale(1.0);

layout/base/MobileViewportManager.cpp

@@ -118,8 +118,8 @@ MobileViewportManager::UpdateResolution(const nsViewportInfo& aViewportInfo,
                                         const CSSSize& aViewport,
                                         const Maybe<float>& aDisplayWidthChangeRatio)
 {
-  CSSToLayoutDeviceScale cssToDev((float)nsPresContext::AppUnitsPerCSSPixel()
-    / mPresShell->GetPresContext()->AppUnitsPerDevPixel());
+  CSSToLayoutDeviceScale cssToDev =
+      mPresShell->GetPresContext()->CSSToDevPixelScale();
   LayoutDeviceToLayerScale res(nsLayoutUtils::GetResolution(mPresShell));
 
   if (mIsFirstPaint) {

layout/base/ZoomConstraintsClient.cpp

@@ -207,9 +207,8 @@ ZoomConstraintsClient::RefreshZoomConstraints()
   if (zoomConstraints.mAllowDoubleTapZoom) {
     // If the CSS viewport is narrower than the screen (i.e. width <= device-width)
     // then we disable double-tap-to-zoom behaviour.
-    int32_t auPerDevPixel = mPresShell->GetPresContext()->AppUnitsPerDevPixel();
-    CSSToLayoutDeviceScale scale(
-      (float)nsPresContext::AppUnitsPerCSSPixel() / auPerDevPixel);
+    CSSToLayoutDeviceScale scale =
+        mPresShell->GetPresContext()->CSSToDevPixelScale();
     if ((viewportInfo.GetSize() * scale).width <= screenSize.width) {
       zoomConstraints.mAllowDoubleTapZoom = false;
     }

layout/base/nsLayoutUtils.cpp

@@ -2486,12 +2486,10 @@ nsLayoutUtils::TransformPoints(nsIFrame* aFromFrame, nsIFrame* aToFrame,
   }
   downToDest.Invert();
   Matrix4x4 upToAncestor = GetTransformToAncestor(aFromFrame, nearestCommonAncestor);
-  CSSToLayoutDeviceScale devPixelsPerCSSPixelFromFrame(
-    double(nsPresContext::AppUnitsPerCSSPixel())/
-      aFromFrame->PresContext()->AppUnitsPerDevPixel());
-  CSSToLayoutDeviceScale devPixelsPerCSSPixelToFrame(
-    double(nsPresContext::AppUnitsPerCSSPixel())/
-      aToFrame->PresContext()->AppUnitsPerDevPixel());
+  CSSToLayoutDeviceScale devPixelsPerCSSPixelFromFrame =
+      aFromFrame->PresContext()->CSSToDevPixelScale();
+  CSSToLayoutDeviceScale devPixelsPerCSSPixelToFrame =
+      aToFrame->PresContext()->CSSToDevPixelScale();
   for (uint32_t i = 0; i < aPointCount; ++i) {
     LayoutDevicePoint devPixels = aPoints[i] * devPixelsPerCSSPixelFromFrame;
     // What should the behaviour be if some of the points aren't invertible
@@ -2970,8 +2968,7 @@ nsLayoutUtils::CalculateBasicFrameMetrics(nsIScrollableFrame* aScrollFrame) {
   FrameMetrics metrics;
   nsPresContext* presContext = frame->PresContext();
   nsIPresShell* presShell = presContext->PresShell();
-  CSSToLayoutDeviceScale deviceScale(float(nsPresContext::AppUnitsPerCSSPixel())
-                                     / presContext->AppUnitsPerDevPixel());
+  CSSToLayoutDeviceScale deviceScale = presContext->CSSToDevPixelScale();
   float resolution = 1.0f;
   if (frame == presShell->GetRootScrollFrame()) {
     // Only the root scrollable frame for a given presShell should pick up
@@ -8399,8 +8396,7 @@ nsLayoutUtils::ComputeFrameMetrics(nsIFrame* aForFrame,
     * nsLayoutUtils::GetTransformToAncestorScale(aScrollFrame ? aScrollFrame : aForFrame));
   metrics.SetExtraResolution(metrics.GetCumulativeResolution() / resolutionToScreen);
 
-  metrics.SetDevPixelsPerCSSPixel(CSSToLayoutDeviceScale(
-    (float)nsPresContext::AppUnitsPerCSSPixel() / auPerDevPixel));
+  metrics.SetDevPixelsPerCSSPixel(presContext->CSSToDevPixelScale());
 
   // Initially, AsyncPanZoomController should render the content to the screen
   // at the painted resolution.