views: Make view::Views::GetPreferredSize() const.

ui/views/layout/grid_layout_unittest.cc

Index: ui/views/layout/grid_layout_unittest.cc
diff --git a/ui/views/layout/grid_layout_unittest.cc b/ui/views/layout/grid_layout_unittest.cc
index 5a7e0fe0527c6234fe3722bbdd02b7318c43af0e..ea7d231f04b459700ba19f409a3fedd05b302279 100644
--- a/ui/views/layout/grid_layout_unittest.cc
+++ b/ui/views/layout/grid_layout_unittest.cc
@@ -24,7 +24,7 @@ class SettableSizeView : public View {
     pref_ = pref;
   }
 
-  virtual gfx::Size GetPreferredSize() OVERRIDE {
+  virtual gfx::Size GetPreferredSize() const OVERRIDE {
     return pref_;
   }
 
@@ -39,11 +39,11 @@ class FlexibleView : public View {
     circumference_ = circumference;
   }
 
-  virtual gfx::Size GetPreferredSize() OVERRIDE {
+  virtual gfx::Size GetPreferredSize() const OVERRIDE {
     return gfx::Size(0, circumference_ / 2);
   }
 
-  virtual int GetHeightForWidth(int width) OVERRIDE {
+  virtual int GetHeightForWidth(int width) const OVERRIDE {
     return std::max(0, circumference_ / 2 - width);
   }