Move prepareForExternalIO implementation from GrContext to GrDrawingManager

src/gpu/GrDrawingManager.cpp

Index: src/gpu/GrDrawingManager.cpp
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index 4642e1a3fe5e491d54856c9bdf1313060482701b..e8cea756228c210e204ac95bca011071c94a6dfc 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -13,6 +13,7 @@
 #include "GrPathRenderingDrawContext.h"
 #include "GrResourceProvider.h"
 #include "GrSoftwarePathRenderer.h"
+#include "GrSurfacePriv.h"
 #include "SkSurface_Gpu.h"
 #include "SkTTopoSort.h"
 
@@ -135,6 +136,23 @@ void GrDrawingManager::internalFlush(GrResourceCache::FlushType type) {
     fFlushing = false;
 }
 
+void GrDrawingManager::prepareSurfaceForExternalIO(GrSurface* surface) {
+    if (this->wasAbandoned()) {
+        return;
+    }
+    SkASSERT(surface);
+    SkASSERT(surface->getContext() == fContext);
+
+    if (surface->surfacePriv().hasPendingIO()) {
+        this->flush();
+    }
+
+    GrRenderTarget* rt = surface->asRenderTarget();
+    if (fContext->getGpu() && rt) {
+        fContext->getGpu()->resolveRenderTarget(rt);
+    }
+}
+
 GrDrawTarget* GrDrawingManager::newDrawTarget(GrRenderTarget* rt) {
     SkASSERT(fContext);