WPF - Change NotifyDpiChange to accept float instead of double

- Double was being cast to float
- If newDpi is same as old DPI do nothing, no extra floating point comparison is being used, so in some cases
it's possible the DPI change will be triggered when the DPI's are actually the same

Author: amaitland

CefSharp.Wpf/ChromiumWebBrowser.cs

@@ -1708,7 +1708,7 @@ private void PresentationSourceChangedHandler(object sender, SourceChangedEventA
 
                 var matrix = source.CompositionTarget.TransformToDevice;
 
-                NotifyDpiChange(matrix.M11);
+                NotifyDpiChange((float)matrix.M11);
 
                 var window = source.RootVisual as Window;
                 if (window != null)
@@ -2436,11 +2436,17 @@ private void ZoomReset()
         /// <param name="newDpi">new DPI</param>
         /// <remarks>.Net 4.6.2 adds HwndSource.DpiChanged which could be used to automatically
         /// handle DPI change, unforunately we still target .Net 4.5.2</remarks>
-        public void NotifyDpiChange(double newDpi)
+        public virtual void NotifyDpiChange(float newDpi)
         {
+            //Do nothing
+            if (DpiScaleFactor.Equals(newDpi))
+            {
+                return;
+            }
+
             var notifyDpiChanged = DpiScaleFactor > 0 && !DpiScaleFactor.Equals(newDpi);
 
-            DpiScaleFactor = (float)newDpi;
+            DpiScaleFactor = newDpi;
 
             if (notifyDpiChanged && browser != null)
             {