Reland: Update iOS deployment target to 7.0

ui/gfx/platform_font_ios.mm

Index: ui/gfx/platform_font_ios.mm
diff --git a/ui/gfx/platform_font_ios.mm b/ui/gfx/platform_font_ios.mm
index 03f5ddbe75a6e986c4f8d2770369d96a60ba53fe..0fd824fcd6373d754d37f6a2c0500d84f310d442 100644
--- a/ui/gfx/platform_font_ios.mm
+++ b/ui/gfx/platform_font_ios.mm
@@ -6,6 +6,8 @@
 
 #import <UIKit/UIKit.h>
 
+#include <cmath>
+
 #include "base/basictypes.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
@@ -110,7 +112,12 @@ void PlatformFontIOS::CalculateMetrics() {
   height_ = font.lineHeight;
   ascent_ = font.ascender;
   cap_height_ = font.capHeight;
-  average_width_ = [@"x" sizeWithFont:font].width;
+  if (font) {
+    NSDictionary* attributes = @{ NSFontAttributeName : font };
+    average_width_ = std::ceil([@"x" sizeWithAttributes:attributes].width);
+  } else {
+    average_width_ = 0;
+  }
 }
 
 ////////////////////////////////////////////////////////////////////////////////