Move HiDPI-related Pepper interfaces to stable

ppapi/cpp/graphics_2d.h

Index: ppapi/cpp/graphics_2d.h
diff --git a/ppapi/cpp/graphics_2d.h b/ppapi/cpp/graphics_2d.h
index 427ea486d88e14d7c127e1d14b353612ab65f0b5..b46467fdc191f75c78d15abe1d20478bde8f9731 100644
--- a/ppapi/cpp/graphics_2d.h
+++ b/ppapi/cpp/graphics_2d.h
@@ -260,6 +260,30 @@ class Graphics2D : public Resource {
   // for it.
   int32_t Flush(const CompletionCallback& cc);
 
+  /// SetScale() sets the scale factor that will be applied when painting the
+  /// graphics context onto the output device. Typically, if rendering at device
+  /// resolution is desired, the context would be created with the width and
+  /// height scaled up by the view's GetDeviceScale and SetScale called with a
+  /// scale of 1.0 / GetDeviceScale(). For example, if the view resource passed
+  /// to DidChangeView has a rectangle of (w=200, h=100) and a device scale of
+  /// 2.0, one would call Create with a size of (w=400, h=200) and then call
+  /// SetScale with 0.5. One would then treat each pixel in the context as a
+  /// single device pixel.
+  ///
+  /// @param[in] scale The scale to apply when painting.
+  ///
+  /// @return Returns <code>true</code> on success or <code>false</code>
+  /// if the resource is invalid or the scale factor is 0 or less.
+  bool SetScale(float scale);
+
+  /// GetScale() gets the scale factor that will be applied when painting the
+  /// graphics context onto the output device.
+  ///
+  /// @return Returns the scale factor for the graphics context. If the resource
+  /// is invalid, 0.0 will be returned. The default scale for a graphics context
+  /// is 1.0.
+  float GetScale();
+
  private:
   Size size_;
 };