Use static_cast instead of reinterpret_cast for downcasting

static_cast is better suited for downcasting since it can check that the
types are related.

/components/data_reduction_proxy
This CL was uploaded by git cl split.

R=tbansal@chromium.org

Change-Id: Idf2ab419bf07cd41493076a887390d93c1f8266a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2435582
Auto-Submit: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813426}

components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.cc

@@ -560,7 +560,7 @@ DataReductionProxyTestContext::data_reduction_proxy_service() const {
 TestDataReductionProxyService*
 DataReductionProxyTestContext::test_data_reduction_proxy_service() const {
   DCHECK(!(test_context_flags_ & USE_MOCK_SERVICE));
-  return reinterpret_cast<TestDataReductionProxyService*>(
+  return static_cast<TestDataReductionProxyService*>(
       data_reduction_proxy_service());
 }
 
@@ -568,21 +568,21 @@ MockDataReductionProxyService*
 DataReductionProxyTestContext::mock_data_reduction_proxy_service() const {
   DCHECK(!(test_context_flags_ & SKIP_SETTINGS_INITIALIZATION));
   DCHECK(test_context_flags_ & USE_MOCK_SERVICE);
-  return reinterpret_cast<MockDataReductionProxyService*>(
+  return static_cast<MockDataReductionProxyService*>(
       data_reduction_proxy_service());
 }
 
 MockDataReductionProxyRequestOptions*
 DataReductionProxyTestContext::mock_request_options() const {
   DCHECK(test_context_flags_ & USE_MOCK_REQUEST_OPTIONS);
-  return reinterpret_cast<MockDataReductionProxyRequestOptions*>(
+  return static_cast<MockDataReductionProxyRequestOptions*>(
       data_reduction_proxy_service()->request_options());
 }
 
 TestDataReductionProxyConfigServiceClient*
 DataReductionProxyTestContext::test_config_client() {
   DCHECK(test_context_flags_ & USE_TEST_CONFIG_CLIENT);
-  return reinterpret_cast<TestDataReductionProxyConfigServiceClient*>(
+  return static_cast<TestDataReductionProxyConfigServiceClient*>(
       data_reduction_proxy_service()->config_client());
 }