Fix format in stack_sampling_profiler.cc

Change-Id: Ifbfd63387c1060f664530ce54963303ff3146fd0
Reviewed-on: https://chromium-review.googlesource.com/1100109Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567136}

base/profiler/stack_sampling_profiler.cc

@@ -860,14 +860,14 @@ bool operator<(const StackSamplingProfiler::Sample& a,
   return a.frames < b.frames;
 }
 
-bool operator==(const StackSamplingProfiler::Frame &a,
-                const StackSamplingProfiler::Frame &b) {
+bool operator==(const StackSamplingProfiler::Frame& a,
+                const StackSamplingProfiler::Frame& b) {
   return a.instruction_pointer == b.instruction_pointer &&
          a.module_index == b.module_index;
 }
 
-bool operator<(const StackSamplingProfiler::Frame &a,
-               const StackSamplingProfiler::Frame &b) {
+bool operator<(const StackSamplingProfiler::Frame& a,
+               const StackSamplingProfiler::Frame& b) {
   if (a.module_index != b.module_index)
     return a.module_index < b.module_index;