Scale client area, hit test mask and bounds by device_scale_factor.

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index 5e8b37d2d29ec593d7aa67ab8d9cea795e9fb481..c2e94634f31f8b9a08eb15d7a83d8913c9688c38 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -38,6 +38,7 @@
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/events/event.h"
+#include "ui/gfx/geometry/dip_util.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -117,6 +118,22 @@ bool IsInternalProperty(const void* key) {
   return key == client::kModalKey;
 }
 
+// Helper function to get the device_scale_factor() of the display::Display
+// with |display_id|.
+float DeviceScaleFactorForDisplay(int64_t display_id) {
+  // TODO(riajiang): Change to use display::GetDisplayWithDisplayId() after
+  // https://codereview.chromium.org/2361283002/ is landed.
+  std::vector<display::Display> displays =
+      display::Screen::GetScreen()->GetAllDisplays();
+  auto iter = std::find_if(displays.begin(), displays.end(),

[sky, 2016/11/09 00:21:13]

When this function is used you always have a window. Can you use
display::Screen::GetScreen()->GetDisplayNearestWindow(window()).device_scale_factor()
?

[riajiang, 2016/11/09 21:07:08]

Changed to use GetDisplayNearestWindow. Kept the TODO since I'm not sure if it
still makes more sense to use GetDisplayWithDisplayId() in the future
(aura::Window doesn't have a display_id)? 

+                           [display_id](const display::Display& display) {
+                             return display.id() == display_id;
+                           });
+  if (iter != displays.end())
+    return iter->device_scale_factor();
+  return 1.f;
+}
+
 }  // namespace
 
 WindowTreeClient::WindowTreeClient(
@@ -204,13 +221,34 @@ void WindowTreeClient::SetClientArea(
     const gfx::Insets& client_area,
     const std::vector<gfx::Rect>& additional_client_areas) {
   DCHECK(tree_);
-  tree_->SetClientArea(WindowMus::Get(window)->server_id(), client_area,
-                       additional_client_areas);
+  float device_scale_factor =
+      DeviceScaleFactorForDisplay(GetWindowTreeHostMus(window)->display_id());

[sky, 2016/11/09 00:21:13]

GetWindowTreeHostMus might return null.

[riajiang, 2016/11/09 21:07:08]

Not using GetWindowTreeHostMus anymore since changed to use
GetDisplayNearestWindow to get the display.

+  if (device_scale_factor == 1.f) {
+    tree_->SetClientArea(WindowMus::Get(window)->server_id(), client_area,
+                         additional_client_areas);
+  } else {
+    std::vector<gfx::Rect> additional_client_areas_in_pixel;
+    for (const gfx::Rect& area : additional_client_areas) {
+      additional_client_areas_in_pixel.push_back(
+          gfx::ConvertRectToPixel(device_scale_factor, area));
+    }
+    tree_->SetClientArea(
+        WindowMus::Get(window)->server_id(),
+        gfx::ConvertInsetsToPixel(device_scale_factor, client_area),
+        additional_client_areas_in_pixel);
+  }
 }
 
 void WindowTreeClient::SetHitTestMask(Window* window, const gfx::Rect& mask) {
   DCHECK(tree_);
-  tree_->SetHitTestMask(WindowMus::Get(window)->server_id(), mask);
+  float device_scale_factor =
+      DeviceScaleFactorForDisplay(GetWindowTreeHostMus(window)->display_id());
+  if (device_scale_factor == 1.f) {
+    tree_->SetHitTestMask(WindowMus::Get(window)->server_id(), mask);
+  } else {
+    tree_->SetHitTestMask(WindowMus::Get(window)->server_id(),
+                          gfx::ConvertRectToPixel(device_scale_factor, mask));
+  }
 }
 
 void WindowTreeClient::ClearHitTestMask(Window* window) {
@@ -947,6 +985,7 @@ void WindowTreeClient::OnClientAreaChanged(
     const gfx::Insets& new_client_area,
     mojo::Array<gfx::Rect> new_additional_client_areas) {
   // TODO: client area.
+  // TODO(riajiang): Convert from pixel to DIP.
   /*
   Window* window = GetWindowByServerId(window_id);
   if (window) {
@@ -1305,6 +1344,7 @@ void WindowTreeClient::WmDisplayModified(const display::Display& display) {
   window_manager_delegate_->OnWmDisplayModified(display);
 }
 
+// TODO(riajiang): Convert between pixel and DIP for window bounds properly.
 void WindowTreeClient::WmSetBounds(uint32_t change_id,
                                    Id window_id,
                                    const gfx::Rect& transit_bounds) {
@@ -1471,8 +1511,19 @@ void WindowTreeClient::SetUnderlaySurfaceOffsetAndExtendedHitArea(
     const gfx::Vector2d& offset,
     const gfx::Insets& hit_area) {
   if (window_manager_internal_client_) {
-    window_manager_internal_client_->SetUnderlaySurfaceOffsetAndExtendedHitArea(
-        WindowMus::Get(window)->server_id(), offset.x(), offset.y(), hit_area);
+    float device_scale_factor =
+        DeviceScaleFactorForDisplay(GetWindowTreeHostMus(window)->display_id());
+    if (device_scale_factor == 1.f) {
+      window_manager_internal_client_
+          ->SetUnderlaySurfaceOffsetAndExtendedHitArea(
+              WindowMus::Get(window)->server_id(), offset.x(), offset.y(),
+              hit_area);
+    } else {
+      window_manager_internal_client_
+          ->SetUnderlaySurfaceOffsetAndExtendedHitArea(
+              WindowMus::Get(window)->server_id(), offset.x(), offset.y(),
+              gfx::ConvertInsetsToDIP(device_scale_factor, hit_area));
+    }
   }
 }