Change PowerStatus::GetBatteryImage to not use ExtractImageRep and scale

ash/common/system/chromeos/power/power_status.h

Index: ash/common/system/chromeos/power/power_status.h
diff --git a/ash/common/system/chromeos/power/power_status.h b/ash/common/system/chromeos/power/power_status.h
index 90d06fff1e2ce62d65695fc8d09b63d9a805222e..2c6104e0aaeb06a849f831bb33633a449648b6f7 100644
--- a/ash/common/system/chromeos/power/power_status.h
+++ b/ash/common/system/chromeos/power/power_status.h
@@ -229,14 +229,12 @@ class ASH_EXPORT PowerStatus : public chromeos::PowerManagerClient::Observer {
   void CalculateBatteryImageInfoNonMd(BatteryImageInfo* info,
                                       const IconSet& icon_set) const;
 
-  // Creates a new image that should be shown for the battery's current state.
-  gfx::ImageSkia GetBatteryImage(const BatteryImageInfo& info) const;
+  // The size of the image GetBatteryImage will return, in DIP.
+  static gfx::Size GetBatteryImageSizeInDip();
 
-  // A version of GetBatteryImage() that is used when material design is not
-  // enabled.
-  // TODO(tdanderson): Remove this once material design is enabled by default.
-  // See crbug.com/614453.
-  gfx::ImageSkia GetBatteryImageNonMd(const BatteryImageInfo& info) const;
+  // Creates a new image that should be shown for the battery's current state.
+  gfx::ImageSkiaRep GetBatteryImage(const BatteryImageInfo& info,
+                                    float scale) const;
 
   // Returns an string describing the current state for accessibility.
   base::string16 GetAccessibleNameString(bool full_description) const;