Fix use-after-move in //components/web_package/

Fix use-after-move (potential) bugs found by the
"bugprone-use-after-move" clang-tidy check.

Bug: 1122844
Change-Id: Ic432627efc292b958b9d30dc3e8886aee02c2b4f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2382832Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802996}

components/web_package/web_bundle_parser_unittest.cc

@@ -45,8 +45,10 @@ class TestDataSource : public mojom::BundleDataSource {
       : data_(reinterpret_cast<const char*>(data.data()), data.size()) {}
 
   void Read(uint64_t offset, uint64_t length, ReadCallback callback) override {
-    if (offset >= data_.size())
+    if (offset >= data_.size()) {
       std::move(callback).Run(base::nullopt);
+      return;
+    }
     const uint8_t* start =
         reinterpret_cast<const uint8_t*>(data_.data()) + offset;
     uint64_t available_length = std::min(length, data_.size() - offset);