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/ProxyTest.cpp b/tests/ProxyTest.cpp
index 40cbeeb..dc34c76 100644
--- a/tests/ProxyTest.cpp
+++ b/tests/ProxyTest.cpp
@@ -52,8 +52,8 @@
     REPORTER_ASSERT(reporter, rtProxy->numStencilSamples() == numSamples);
 
     GrSurfaceProxy::UniqueID idBefore = rtProxy->uniqueID();
-    GrRenderTarget* rt = rtProxy->instantiateRenderTarget(provider);
-    REPORTER_ASSERT(reporter, rt);
+    REPORTER_ASSERT(reporter, rtProxy->instantiate(provider));
+    GrRenderTarget* rt = rtProxy->priv().peekRenderTarget();
 
     REPORTER_ASSERT(reporter, rtProxy->uniqueID() == idBefore);
     if (wasWrapped) {
@@ -86,8 +86,9 @@
                           SkBackingFit fit,
                           bool wasWrapped) {
     GrSurfaceProxy::UniqueID idBefore = texProxy->uniqueID();
-    GrTexture* tex = texProxy->instantiateTexture(provider);
-    REPORTER_ASSERT(reporter, tex);
+
+    REPORTER_ASSERT(reporter, texProxy->instantiate(provider));
+    GrTexture* tex = texProxy->priv().peekTexture();
 
     REPORTER_ASSERT(reporter, texProxy->uniqueID() == idBefore);
     if (wasWrapped) {