Implement the color matrix filter in Ganesh.  Also, fix and enable the color
matrix test slide.  This was basically implemented in the same places where
the blending-based color filter was being done.  The shader simply does a mat4
matrix multiply and a vec4 add.

Review URL:  http://codereview.appspot.com/5489107/



git-svn-id: http://skia.googlecode.com/svn/trunk@2948 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrGLShaderVar.h b/src/gpu/GrGLShaderVar.h
index 5f1ba03..1d5d7ca 100644
--- a/src/gpu/GrGLShaderVar.h
+++ b/src/gpu/GrGLShaderVar.h
@@ -27,6 +27,7 @@
         kVec3f_Type,
         kVec4f_Type,
         kMat33f_Type,
+        kMat44f_Type,
         kSampler2D_Type,
     };
 
@@ -242,6 +243,8 @@
                 return "vec4";
             case kMat33f_Type:
                 return "mat3";
+            case kMat44f_Type:
+                return "mat4";
             case kSampler2D_Type:
                 return "sampler2D";
             default: