chromeos/input: Fix warning with 32-bit builds

The format specifier for a int64_t argument was %ld, which works fine on
64-bit architectures but corresponds to a 32-bit long on 32-bit archs.

Fix this by using the PRId64 specifier that will work on all
architectures.

BUG=None.
TEST=Chrome builds for arm-generic.

Change-Id: Iee32204df9f52fe2a6dd9ceb05edee22ff5e14f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1993068
Commit-Queue: Alexandre Courbot <acourbot@chromium.org>
Auto-Submit: Alexandre Courbot <acourbot@chromium.org>
Reviewed-by: Keith Lee <keithlee@chromium.org>
Reviewed-by: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#730052}

chrome/browser/chromeos/input_method/input_method_manager_impl.cc

@@ -7,6 +7,7 @@
 #include <stdint.h>
 
 #include <algorithm>  // std::find
+#include <cstdint>
 #include <memory>
 #include <set>
 #include <sstream>
@@ -1348,9 +1349,9 @@ void InputMethodManagerImpl::OverrideKeyboardKeyset(
   // the frontend will reload.
   auto ts_start = overridden_ref.find("&ts=");
   std::string ts_tag =
-      base::StringPrintf("&ts=%ld", base::Time::NowFromSystemTime()
-                                        .ToDeltaSinceWindowsEpoch()
-                                        .InMicroseconds());
+      base::StringPrintf("&ts=%" PRId64, base::Time::NowFromSystemTime()
+                                             .ToDeltaSinceWindowsEpoch()
+                                             .InMicroseconds());
   if (ts_start == std::string::npos) {
     overridden_ref += ts_tag;
   } else {