Add deferred texture upload API.

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 8844f1ac838a887ce2a437b49e55cd7f6abc70e0..97b68d150474f5fc73d776ad15a0224c6d02be03 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -127,6 +127,13 @@ GrContext::~GrContext() {
     fCaps->unref();
 }
 

[robertphillips, 2016/03/08 18:43:10]

Should we make threadSafeProxy thread safe itself?

[bsalomon, 2016/03/08 19:49:32]

GrContext is not thread-safe so I don't think this method should be expected to
be thread-safe and I think it'll get complicated to document which methods are
thread safe.

+GrContextThreadSafeProxy* GrContext::threadSafeProxy() {
+    if (!fThreadSafeProxy) {
+        fThreadSafeProxy.reset(new GrContextThreadSafeProxy(fCaps, this->uniqueID()));
+    }
+    return SkRef(fThreadSafeProxy.get());
+}
+
 void GrContext::abandonContext() {
     ASSERT_SINGLE_OWNER