Rename and clarify semantics of GrContext::resolveRenderTarget.

src/gpu/GrSurface.cpp

Index: src/gpu/GrSurface.cpp
diff --git a/src/gpu/GrSurface.cpp b/src/gpu/GrSurface.cpp
index 0aa5f681ab2d1a07657e9814b77ff20b039d9766..1779f2441b46747cbc936cdc9c16d0eadc4311f2 100644
--- a/src/gpu/GrSurface.cpp
+++ b/src/gpu/GrSurface.cpp
@@ -82,6 +82,12 @@ void GrSurface::flushWrites() {
     }
 }
 
+void GrSurface::prepareForExternalRead() {
+    if (!this->wasDestroyed()) {
+        this->getContext()->prepareSurfaceForExternalRead(this);
+    }
+}
+
 bool GrSurface::hasPendingRead() const {
     const GrTexture* thisTex = this->asTexture();
     if (thisTex && thisTex->internalHasPendingRead()) {