Return after callback on failure in GrRenderTargetContext::asyncReadP…

…ixels

Bug: chromium:1048251
Change-Id: I9c18e55fd791adbf446aa776de297b857af22b64
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/269237
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
(cherry picked from commit 4bb5026)
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/270178
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

src/gpu/GrRenderTargetContext.cpp

@@ -1875,6 +1875,7 @@ void GrRenderTargetContext::asyncReadPixels(const SkIRect& rect, SkColorType col
 
         if (!this->readPixels(ii, pm.writable_addr(), pm.rowBytes(), {rect.fLeft, rect.fTop})) {
             callback(context, nullptr);
+            return;
         }
         callback(context, std::move(result));
         return;