Disable High DPI Canvas on iOS
https://bugs.webkit.org/show_bug.cgi?id=112511

Reviewed by Joseph Pecoraro.

Source/JavaScriptCore:

* Configurations/FeatureDefines.xcconfig:

Source/WebCore:

* Configurations/FeatureDefines.xcconfig:

Source/WebKit/mac:

* Configurations/FeatureDefines.xcconfig:

Source/WebKit2:

* Configurations/FeatureDefines.xcconfig:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146006 268f45cc-cd09-0410-ab3c-d52691b4dbfc