Convert GrClip to an abstract base class

tools/gpu/GrTest.cpp

Index: tools/gpu/GrTest.cpp
diff --git a/tools/gpu/GrTest.cpp b/tools/gpu/GrTest.cpp
index 874567dc62ee6c58486197e7bd5af961d90ab179..a301c747cac32b0ca23a6aba6eb72b0623464c77 100644
--- a/tools/gpu/GrTest.cpp
+++ b/tools/gpu/GrTest.cpp
@@ -168,8 +168,7 @@ void SkGpuDevice::drawTexture(GrTexture* tex, const SkRect& dst, const SkPaint&
 
     grPaint.addColorTextureProcessor(tex, textureMat);
 
-    GrClip clip;
-    fDrawContext->drawRect(clip, grPaint, mat, dst);
+    fDrawContext->drawRect(GrNoClip(), grPaint, mat, dst);
 }
 
 
@@ -260,8 +259,11 @@ void GrDrawContextPriv::testingOnly_drawBatch(const GrPipelineBuilder& pipelineB
     SkDEBUGCODE(fDrawContext->validate();)
     GR_AUDIT_TRAIL_AUTO_FRAME(fDrawContext->fAuditTrail, "GrDrawContext::testingOnly_drawBatch");
 
-    const GrClip& drawClip = clip ? *clip : GrClip::WideOpen();
-    fDrawContext->getDrawTarget()->drawBatch(pipelineBuilder, drawClip, batch);
+    if (clip) {
+        fDrawContext->getDrawTarget()->drawBatch(pipelineBuilder, *clip, batch);
+    } else {
+        fDrawContext->getDrawTarget()->drawBatch(pipelineBuilder, GrNoClip(), batch);
+    }
 }
 
 #undef ASSERT_SINGLE_OWNER