Make DesktopResizer use ScreenResolution to facilitate DPI-awareness.

remoting/host/screen_resolution.h

Index: remoting/host/screen_resolution.h
diff --git a/remoting/host/screen_resolution.h b/remoting/host/screen_resolution.h
index 81690db701a2a877789514bd8cd364ffb66bb441..8adc25e3d69e155ff03fd955ea67ba71f1dc6ebe 100644
--- a/remoting/host/screen_resolution.h
+++ b/remoting/host/screen_resolution.h
@@ -32,6 +32,9 @@ class ScreenResolution {
   // IsValid() returns false.
   bool IsEmpty() const;
 
+  // Returns true if the dimensions and DPI of the two resolutions match.
+  bool Equals(const ScreenResolution& other) const;
+
  private:
   webrtc::DesktopSize dimensions_;
   webrtc::DesktopVector dpi_;