Full Screen Magnifier: Add MagnificationManager

ash/magnifier/magnification_controller.cc

Index: ash/magnifier/magnification_controller.cc
diff --git a/ash/magnifier/magnification_controller.cc b/ash/magnifier/magnification_controller.cc
index 1fa8244701377e3c0ff43412473b5a2ba9409c72..8bec3c9094d80237bb35f115f986c705e22049e2 100644
--- a/ash/magnifier/magnification_controller.cc
+++ b/ash/magnifier/magnification_controller.cc
@@ -46,6 +46,7 @@ class MagnificationControllerImpl : virtual public MagnificationController,
 
   // MagnificationController overrides:
   virtual void SetEnabled(bool enabled) OVERRIDE;
+  virtual bool IsEnabled() OVERRIDE { return is_enabled_; }
   virtual void SetScale(float scale, bool animate) OVERRIDE;
   virtual float GetScale() const OVERRIDE { return scale_; }
   virtual void MoveWindow(int x, int y, bool animate) OVERRIDE;
@@ -417,6 +418,8 @@ void MagnificationControllerImpl::SetEnabled(bool enabled) {
   if (enabled) {
     float scale =
         ash::Shell::GetInstance()->delegate()->GetSavedScreenMagnifierScale();
+    if (scale <= 0.0f)
+      scale = kInitialMagnifiedScale;
     ValidateScale(&scale);
     RedrawKeepingMousePosition(scale, true);
     is_enabled_ = enabled;