Fix cpplint errors.

The only non-obvious change here is the switch from dynamic_cast to
static_cast in three cases of down-casting in UpdateAttempter.
dynamic_cast is banned by style, nor does it add any safety in this
particular case (subsequent code dereferences the result right away
without checking whether it's null).

BUG=None
TEST=None

Change-Id: I9d49b46362feaf9c6fa13b2715ebe9fe50308a9a
Reviewed-on: https://chromium-review.googlesource.com/207470
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/update_attempter.cc b/update_attempter.cc
index 24f727b..6ee9f4d 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -982,11 +982,11 @@
   const string type = action->Type();
   if (type == DownloadAction::StaticType()) {
     download_progress_ = 0.0;
-    DownloadAction* download_action = dynamic_cast<DownloadAction*>(action);
+    DownloadAction* download_action = static_cast<DownloadAction*>(action);
     http_response_code_ = download_action->GetHTTPResponseCode();
   } else if (type == OmahaRequestAction::StaticType()) {
     OmahaRequestAction* omaha_request_action =
-        dynamic_cast<OmahaRequestAction*>(action);
+        static_cast<OmahaRequestAction*>(action);
     // If the request is not an event, then it's the update-check.
     if (!omaha_request_action->IsEvent()) {
       http_response_code_ = omaha_request_action->GetHTTPResponseCode();
@@ -1365,7 +1365,7 @@
 
 void UpdateAttempter::SetupDownload() {
   MultiRangeHttpFetcher* fetcher =
-      dynamic_cast<MultiRangeHttpFetcher*>(download_action_->http_fetcher());
+      static_cast<MultiRangeHttpFetcher*>(download_action_->http_fetcher());
   fetcher->ClearRanges();
   if (response_handler_action_->install_plan().is_resume) {
     // Resuming an update so fetch the update manifest metadata first.