Make a bunch of virtuals in GrDrawTarget and GrGpu private. Subclasses shouldn't call them directly.

R=robertphillips@google.com
Review URL: https://codereview.appspot.com/7228048

git-svn-id: http://skia.googlecode.com/svn/trunk@7413 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 70fdff9..b0bac8a 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -942,7 +942,7 @@
     for (int s = drawState.getFirstCoverageStage();
          !hasCoverage && s < GrDrawState::kNumStages;
          ++s) {
-        if (this->isStageEnabled(s)) {
+        if (drawState.isStageEnabled(s)) {
             hasCoverage = true;
         }
     }
@@ -1145,6 +1145,9 @@
     }
 }
 
+void GrDrawTarget::clipWillBeSet(const GrClipData* clipData) {
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 GrDrawTarget::AutoStateRestore::AutoStateRestore() {