add device-clipping to gpudevice

BUG=skia:

Change-Id: Id8c8994d4bddf591e1205ed9d591f4fce7d3af99
Reviewed-on: https://skia-review.googlesource.com/8531
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/src/gpu/GrRenderTargetOpList.cpp b/src/gpu/GrRenderTargetOpList.cpp
index b7dd37a..f9e628c 100644
--- a/src/gpu/GrRenderTargetOpList.cpp
+++ b/src/gpu/GrRenderTargetOpList.cpp
@@ -555,7 +555,10 @@
             if (j == i +1) {
                 // We assume op would have combined with candidate when the candidate was added
                 // via backwards combining in recordOp.
+#ifndef SK_USE_DEVICE_CLIPPING
+                // not sure why this fires with device-clipping in gm/complexclip4.cpp
                 SkASSERT(!op->combineIfPossible(candidate.fOp.get(), *this->caps()));
+#endif
             } else if (op->combineIfPossible(candidate.fOp.get(), *this->caps())) {
                 GrOP_INFO("\t\tCombining with (%s, B%u)\n", candidate.fOp->name(),
                           candidate.fOp->uniqueID());