Use GetDeviceScaleFactor to get scale factor for coord space transform

The device scale factor is not properly applied in
CrossProcessFrameConnector::TransformPointToLocalCoordSpaceLegacy
We're using current_surface_scale_factor() which does not seem to
provide the correct value. We want GetDeviceScaleFactor().

Test: SitePerProcessInternalsHitTestBrowserTest.ScrollNestedLocalNonFastScrollableDiv
after crrev.com/c/1427607 landed

Bug: 923069
Change-Id: Iae748780d0657d7674cf4ba76a276ad03cc28a74
Reviewed-on: https://chromium-review.googlesource.com/c/1435834Reviewed-by: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Jianpeng Chao <chaopeng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626115}

content/browser/frame_host/cross_process_frame_connector.cc

@@ -225,15 +225,15 @@ bool CrossProcessFrameConnector::TransformPointToLocalCoordSpaceLegacy(
   // Transformations use physical pixels rather than DIP, so conversion
   // is necessary.
   *transformed_point =
-      gfx::ConvertPointToPixel(view_->current_surface_scale_factor(), point);
+      gfx::ConvertPointToPixel(view_->GetDeviceScaleFactor(), point);
   viz::SurfaceHittest hittest(nullptr,
                               GetFrameSinkManager()->surface_manager());
   if (!hittest.TransformPointToTargetSurface(original_surface, local_surface_id,
                                              transformed_point))
     return false;
 
-  *transformed_point = gfx::ConvertPointToDIP(
-      view_->current_surface_scale_factor(), *transformed_point);
+  *transformed_point =
+      gfx::ConvertPointToDIP(view_->GetDeviceScaleFactor(), *transformed_point);
   return true;
 }
 

content/browser/frame_host/render_widget_host_view_guest.cc

@@ -272,8 +272,7 @@ bool RenderWidgetHostViewGuest::TransformPointToLocalCoordSpaceLegacy(
   if (original_surface == surface_id)
     return true;
 
-  *transformed_point =
-      gfx::ConvertPointToPixel(current_surface_scale_factor(), point);
+  *transformed_point = gfx::ConvertPointToPixel(GetDeviceScaleFactor(), point);
   viz::SurfaceHittest hittest(nullptr,
                               GetFrameSinkManager()->surface_manager());
   if (!hittest.TransformPointToTargetSurface(original_surface, surface_id,
@@ -281,8 +280,8 @@ bool RenderWidgetHostViewGuest::TransformPointToLocalCoordSpaceLegacy(
     return false;
   }
 
-  *transformed_point = gfx::ConvertPointToDIP(current_surface_scale_factor(),
-                                              *transformed_point);
+  *transformed_point =
+      gfx::ConvertPointToDIP(GetDeviceScaleFactor(), *transformed_point);
   return true;
 }
 

content/browser/renderer_host/render_widget_host_view_child_frame.h

@@ -212,11 +212,6 @@ class CONTENT_EXPORT RenderWidgetHostViewChildFrame
     return frame_connector_;
   }
 
-  // Returns the current surface scale factor.
-  float current_surface_scale_factor() {
-    return last_activated_surface_info_.device_scale_factor();
-  }
-
   // Returns the view into which this view is directly embedded. This can
   // return nullptr when this view's associated child frame is not connected
   // to the frame tree.