Make copySurface work for texture dsts, return a bool, & add unit test.

src/gpu/GrDrawContext.cpp

Index: src/gpu/GrDrawContext.cpp
diff --git a/src/gpu/GrDrawContext.cpp b/src/gpu/GrDrawContext.cpp
index f37c48c9f3792c479a98d36a74deb5ea1996bdf5..d971f58ece1ce20156cf6a225e7b263ec8030966 100644
--- a/src/gpu/GrDrawContext.cpp
+++ b/src/gpu/GrDrawContext.cpp
@@ -97,13 +97,13 @@ GrDrawTarget* GrDrawContext::getDrawTarget() {
     return fDrawTarget;
 }
 
-void GrDrawContext::copySurface(GrSurface* src, const SkIRect& srcRect, const SkIPoint& dstPoint) {
+bool GrDrawContext::copySurface(GrSurface* src, const SkIRect& srcRect, const SkIPoint& dstPoint) {
     ASSERT_SINGLE_OWNER
-    RETURN_IF_ABANDONED
+    RETURN_FALSE_IF_ABANDONED
     SkDEBUGCODE(this->validate();)
     GR_AUDIT_TRAIL_AUTO_FRAME(fAuditTrail, "GrDrawContext::copySurface");
 
-    this->getDrawTarget()->copySurface(fRenderTarget, src, srcRect, dstPoint);
+    return this->getDrawTarget()->copySurface(fRenderTarget, src, srcRect, dstPoint);
 }
 
 void GrDrawContext::drawText(const GrClip& clip, const GrPaint& grPaint,