Remove use of long long

In preparation for moving ui/chromeos/ime to
chrome/browser/chromeos/input_method/ui, fix presubmit errors.

Change-Id: I488bf5d81a3b541d8954c89456a15aafe0602323
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2228429Reviewed-by: Keith Lee <keithlee@chromium.org>
Commit-Queue: My Nguyen <myy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776377}

ui/chromeos/ime/candidate_window_view_unittest.cc

@@ -55,10 +55,8 @@ void InitCandidateWindowWithCandidatesFilled(
   InitCandidateWindow(page_size, candidate_window);
   for (size_t i = 0; i < page_size; ++i) {
     ui::CandidateWindow::Entry entry;
-    entry.value = base::UTF8ToUTF16(base::StringPrintf(
-        "value %lld", static_cast<unsigned long long>(i)));
-    entry.label = base::UTF8ToUTF16(base::StringPrintf(
-        "%lld", static_cast<unsigned long long>(i)));
+    entry.value = base::UTF8ToUTF16(base::StringPrintf("value %zu", i));
+    entry.label = base::UTF8ToUTF16(base::StringPrintf("%zu", i));
     candidate_window->mutable_candidates()->push_back(entry);
   }
 }