exo: Fix cursor scaling for 1.25 DSF

components/exo/pointer.cc

Index: components/exo/pointer.cc
diff --git a/components/exo/pointer.cc b/components/exo/pointer.cc
index 5d2b915e85b8e37c13916cec856420c72b182329..6e7b55f2f62a10175565c3408db886856f0b189c 100644
--- a/components/exo/pointer.cc
+++ b/components/exo/pointer.cc
@@ -4,8 +4,8 @@
 
 #include "components/exo/pointer.h"
 
-#include <algorithm>
 #include <numeric>
+#include <tuple>
 #include <utility>
 
 #include "ash/public/cpp/shell_window_ids.h"
@@ -272,12 +272,16 @@ void Pointer::OnDisplayConfigurationChanged() {
   UpdatePointerSurface(surface_);
 
   const auto& displays = display::Screen::GetScreen()->GetAllDisplays();
-  capture_scale_ = std::accumulate(
-      displays.begin(), displays.end(), 1.0f,
-      [](float scale, const display::Display& display) -> float {
+  using ScalePair = std::pair<float, float>;
+  std::tie(capture_scale_, capture_ratio_) = std::accumulate(

[reveman, 2017/06/19 22:20:39]

heh, cool; but I think you've crossed the line to where having simple for-loop
is easier to read :)

[Dominik Laskowski, 2017/06/20 15:52:35]

Yeah, even the original was pushing it. Done.

+      displays.begin(), displays.end(), ScalePair(1.0f, 1.0f),
+      [](const ScalePair& pair, const display::Display& display) -> ScalePair {
         const auto& info =
             WMHelper::GetInstance()->GetDisplayInfo(display.id());
-        return std::max(scale, info.device_scale_factor());
+        return info.device_scale_factor() > pair.first
+                   ? ScalePair(info.device_scale_factor(),
+                               info.GetDensityRatio())
+                   : pair;
       });
 }
 
@@ -389,12 +393,12 @@ void Pointer::UpdateCursor() {
     cursor_ = ui::CursorType::kNone;
   } else {
     SkBitmap bitmap = cursor_bitmap_;
-    gfx::Point hotspot = gfx::ScaleToFlooredPoint(hotspot_, capture_scale_);
+    gfx::Point hotspot = gfx::ScaleToFlooredPoint(hotspot_, capture_ratio_);
 
     auto* helper = WMHelper::GetInstance();
     const display::Display& display = helper->GetCursorDisplay();
-    float scale = helper->GetDisplayInfo(display.id()).device_scale_factor() /
-                  capture_scale_;
+    float scale =
+        helper->GetDisplayInfo(display.id()).GetDensityRatio() / capture_ratio_;
 
     if (helper->GetCursorSet() == ui::CURSOR_SET_LARGE)
       scale *= kLargeCursorScale;