[memory-infra] Fix base_unittests on CFI bots

base/trace_event/memory_dump_scheduler.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/trace_event/memory_dump_scheduler.h"
 
 #include "base/process/process_metrics.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
@@ skipping 264 matching lines @@
 }
 
 void MemoryDumpScheduler::PollingTriggerState::ResetTotals() {
   if (!memory_increase_threshold) {
     memory_increase_threshold = kDefaultMemoryIncreaseThreshold;
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX) || \
     defined(OS_ANDROID)
     // Set threshold to 1% of total system memory.
     SystemMemoryInfoKB meminfo;
     bool res = GetSystemMemoryInfo(&meminfo);
-    if (res)
-      memory_increase_threshold = (meminfo.total / 100) * 1024;
+    if (res) {
+      memory_increase_threshold =
+          (static_cast<int64_t>(meminfo.total) / 100) * 1024;
+    }
+    DCHECK_GT(memory_increase_threshold, 0u);
 #endif
   }
 
   // Update the |last_dump_memory_total|'s value from the totals if it's not
   // first poll.
   if (num_polls_from_last_dump >= 0 &&
       last_memory_totals_kb[last_memory_totals_kb_index]) {
     last_dump_memory_total =
         last_memory_totals_kb[last_memory_totals_kb_index] * 1024;
   }
   num_polls_from_last_dump = 0;
   for (uint32_t i = 0; i < kMaxNumMemorySamples; ++i)
     last_memory_totals_kb[i] = 0;
   last_memory_totals_kb_index = 0;
 }
 
 }  // namespace trace_event
 }  // namespace base