Remove getter of writable GrEffectStage from GrDrawState.

Upcoming changes will require GrDrawState to know things about the set of installed effects. Thus all setting of effects must go through a GrDrawState function (setEffect()). This change accomplishes that.
Review URL: https://codereview.appspot.com/7214045

git-svn-id: http://skia.googlecode.com/svn/trunk@7411 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/GLProgramsTest.cpp b/tests/GLProgramsTest.cpp
index e83ddeb..f9dd918 100644
--- a/tests/GLProgramsTest.cpp
+++ b/tests/GLProgramsTest.cpp
@@ -169,12 +169,10 @@
 void forceLinking() {
     SkLightingImageFilter::CreateDistantLitDiffuse(SkPoint3(0,0,0), 0, 0, 0);
     SkMagnifierImageFilter mag(SkRect::MakeWH(SK_Scalar1, SK_Scalar1), SK_Scalar1);
-    GrEffectStage dummyStage;
-    GrConfigConversionEffect::InstallEffect(NULL,
-                                            false,
-                                            GrConfigConversionEffect::kNone_PMConversion,
-                                            SkMatrix::I(),
-                                            &dummyStage);
+    GrConfigConversionEffect::Create(NULL,
+                                     false,
+                                     GrConfigConversionEffect::kNone_PMConversion,
+                                     SkMatrix::I());
     SkScalar matrix[20];
     SkColorMatrixFilter cmf(matrix);
 }