More framework support for TransferBuffers

src/gpu/GrGpu.cpp

Index: src/gpu/GrGpu.cpp
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index e2457ce31e4f47325e81ba1c3f744678e1399c24..2815f612d602707c2186d1348d8deca5ba45c426 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -334,7 +334,7 @@ bool GrGpu::writePixels(GrSurface* surface,
                         int left, int top, int width, int height,
                         GrPixelConfig config, const void* buffer,
                         size_t rowBytes) {
-    if (!buffer) {
+    if (!buffer || !surface) {
         return false;
     }
 
@@ -346,6 +346,21 @@ bool GrGpu::writePixels(GrSurface* surface,
     return false;
 }
 
+bool GrGpu::transferPixels(GrSurface* surface,
+                           int left, int top, int width, int height,
+                           GrPixelConfig config, GrTransferBuffer* buffer,
+                           size_t offset, size_t rowBytes) {
+    SkASSERT(buffer);
+
+    this->handleDirtyContext();
+    if (this->onTransferPixels(surface, left, top, width, height, config, 
+                               buffer, offset, rowBytes)) {
+        fStats.incTransfersToTexture();
+        return true;
+    }
+    return false;
+}
+
 void GrGpu::resolveRenderTarget(GrRenderTarget* target) {
     SkASSERT(target);
     this->handleDirtyContext();