Add :indeterminate pseudo class support for radio button input

Source/platform/mac/ThemeMac.mm

 /*
  * Copyright (C) 2008, 2010, 2011, 2012 Apple Inc. All Rights Reserved.
  *
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  * modification, are permitted provided that the following conditions
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@@ skipping 331 matching lines @@
         radioCell = [[NSButtonCell alloc] init];
         [radioCell setButtonType:NSRadioButton];
         [radioCell setTitle:nil];
         [radioCell setFocusRingType:NSFocusRingTypeExterior];
     }
     
     // Set the control size based off the rectangle we're painting into.
     setControlSize(radioCell, radioSizes(), zoomedRect.size(), zoomFactor);
 
     // Update the various states we respond to.
+    // Cocoa draws NSMixedState NSRadioButton as NSOnState so we don't want that.
+    states &= ~IndeterminateControlState;

[tkent, 2014/07/15 01:31:50]

Do we have a pixel test for indeterminate radio buttons?
If not, we should add it to fast/forms/radio/radio-appearance-basic.html.

[keishi, 2014/07/15 03:05:30]

All elements in radio-appearance-basic.html are not in a radio button group so
the unchecked ones have the indeterminate appearance. I added a not
indeterminate not checked test to radio-appearance-basic.html.

     updateStates(radioCell, states);
     
     return radioCell;
 }
 
 static void paintRadio(ControlStates states, GraphicsContext* context, const IntRect& zoomedRect, float zoomFactor, ScrollView* scrollView)
 {
     // Determine the width and height needed for the control and prepare the cell for painting.
     NSButtonCell *radioCell = radio(states, zoomedRect, zoomFactor);
     GraphicsContextStateSaver stateSaver(*context);
@@ skipping 357 matching lines @@
             break;
         case InnerSpinButtonPart:
             paintStepper(states, context, zoomedRect, zoomFactor, scrollView);
             break;
         default:
             break;
     }
 }
 
 }