Make instantiate return a Boolean

From an off-line conversation:
The longer term idea will be to create a helper class isolates the
ability to instantiate proxies until flush time. The peek* methods
could then be moved to GrSurfaceProxy.

Change-Id: I8e8c02c098475b77d515791c0d6b81f7e4a327dd
Reviewed-on: https://skia-review.googlesource.com/18076
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/tests/ClipStackTest.cpp b/tests/ClipStackTest.cpp
index ba80933..e0df2ca 100644
--- a/tests/ClipStackTest.cpp
+++ b/tests/ClipStackTest.cpp
@@ -16,6 +16,7 @@
 #include "GrClipStackClip.h"
 #include "GrReducedClip.h"
 #include "GrResourceCache.h"
+#include "GrSurfaceProxyPriv.h"
 #include "GrTextureProxy.h"
 typedef GrReducedClip::ElementList ElementList;
 typedef GrReducedClip::InitialState InitialState;
@@ -1442,7 +1443,8 @@
         stack.save();
         stack.clipPath(path, m, SkClipOp::kIntersect, true);
         sk_sp<GrTextureProxy> mask = GrClipStackClip(&stack).testingOnly_createClipMask(context);
-        GrTexture* tex = mask->instantiateTexture(context->resourceProvider());
+        mask->instantiate(context->resourceProvider());
+        GrTexture* tex = mask->priv().peekTexture();
         REPORTER_ASSERT(reporter, 0 == strcmp(tex->getUniqueKey().tag(), kTag));
         // Make sure mask isn't pinned in cache.
         mask.reset(nullptr);