gfx: Rename canvas SaveAndUnscale to UnscaleTheDeviceScaleFactor.

ui/gfx/canvas.h

Index: ui/gfx/canvas.h
diff --git a/ui/gfx/canvas.h b/ui/gfx/canvas.h
index 8183dfae02102461c56144b43426a9af161e19a8..30e2deddd65b5165e432a79ebb0b7349a723b456 100644
--- a/ui/gfx/canvas.h
+++ b/ui/gfx/canvas.h
@@ -165,15 +165,15 @@ class GFX_EXPORT Canvas {
   // Draws a dashed rectangle of the specified color.
   void DrawDashedRect(const Rect& rect, SkColor color);
 
+  // Unscales by the image scale factor (aka device scale factor), and returns
+  // that factor.  This is useful when callers want to draw directly in the
+  // native scale.
+  float UnscaleTheDeviceScaleFactor();

[Peter Kasting, 2015/10/29 23:11:10]

This name is so verbose it reads poorly.  How about "UndoDeviceScale()", which
is admittedly slightly less accurate but seems clear enough and a lot less
wordy.

Or you could go in another direction and do "PrepareForPixelDrawing()" or the
like.

[sky, 2015/10/29 23:37:54]

+1 to Peter's first suggestion UndoDeviceScale.

[danakj, 2015/10/30 17:51:21]

Done. I used UndoDeviceScaleFactor(), because we never write just DeviceScale
(in code I've read), and often shorten to DSF in conversation etc.

+
   // Saves a copy of the drawing state onto a stack, operating on this copy
   // until a balanced call to Restore() is made.
   void Save();
 
-  // Saves the drawing state, unscales by the image scale factor, and returns
-  // that factor.  This is useful when callers want to draw directly in the
-  // native scale.
-  float SaveAndUnscale();
-
   // As with Save(), except draws to a layer that is blended with the canvas
   // at the specified alpha once Restore() is called.
   // |layer_bounds| are the bounds of the layer relative to the current