Represent speed in GCTracer functions as double instead of int.

src/heap/scavenge-job.cc

Index: src/heap/scavenge-job.cc
diff --git a/src/heap/scavenge-job.cc b/src/heap/scavenge-job.cc
index 52ba97a9c7bab9f64769f031e328903d95a271f0..d89c9453c50bb19da5aca78cda23a544ce4ce139 100644
--- a/src/heap/scavenge-job.cc
+++ b/src/heap/scavenge-job.cc
@@ -23,8 +23,8 @@ void ScavengeJob::IdleTask::RunInternal(double deadline_in_seconds) {
       static_cast<double>(base::Time::kMillisecondsPerSecond);
   double start_ms = heap->MonotonicallyIncreasingTimeInMs();
   double idle_time_in_ms = deadline_in_ms - start_ms;
-  size_t scavenge_speed_in_bytes_per_ms =
-      static_cast<size_t>(heap->tracer()->ScavengeSpeedInBytesPerMillisecond());
+  double scavenge_speed_in_bytes_per_ms =
+      heap->tracer()->ScavengeSpeedInBytesPerMillisecond();
   size_t new_space_size = heap->new_space()->Size();
   size_t new_space_capacity = heap->new_space()->Capacity();
 
@@ -42,9 +42,8 @@ void ScavengeJob::IdleTask::RunInternal(double deadline_in_seconds) {
   }
 }
 
-
 bool ScavengeJob::ReachedIdleAllocationLimit(
-    size_t scavenge_speed_in_bytes_per_ms, size_t new_space_size,
+    double scavenge_speed_in_bytes_per_ms, size_t new_space_size,
     size_t new_space_capacity) {
   if (scavenge_speed_in_bytes_per_ms == 0) {
     scavenge_speed_in_bytes_per_ms = kInitialScavengeSpeedInBytesPerMs;
@@ -52,27 +51,24 @@ bool ScavengeJob::ReachedIdleAllocationLimit(
 
   // Set the allocation limit to the number of bytes we can scavenge in an
   // average idle task.
-  size_t allocation_limit = kAverageIdleTimeMs * scavenge_speed_in_bytes_per_ms;
+  double allocation_limit = kAverageIdleTimeMs * scavenge_speed_in_bytes_per_ms;
 
   // Keep the limit smaller than the new space capacity.
   allocation_limit =
-      Min(allocation_limit,
-          static_cast<size_t>(new_space_capacity *
-                              kMaxAllocationLimitAsFractionOfNewSpace));
+      Min<double>(allocation_limit,
+                  new_space_capacity * kMaxAllocationLimitAsFractionOfNewSpace);
   // Adjust the limit to take into account bytes that will be allocated until
-  // the next check.
-  allocation_limit = allocation_limit < kBytesAllocatedBeforeNextIdleTask
-                         ? 0
-                         : allocation_limit - kBytesAllocatedBeforeNextIdleTask;
-  // Keep the limit large enough to avoid scavenges in tiny new space.
-  allocation_limit = Max(allocation_limit, kMinAllocationLimit);
+  // the next check and keep the limit large enough to avoid scavenges in tiny
+  // new space.
+  allocation_limit =
+      Max<double>(allocation_limit - kBytesAllocatedBeforeNextIdleTask,
+                  kMinAllocationLimit);
 
   return allocation_limit <= new_space_size;
 }
 
-
 bool ScavengeJob::EnoughIdleTimeForScavenge(
-    double idle_time_in_ms, size_t scavenge_speed_in_bytes_per_ms,
+    double idle_time_in_ms, double scavenge_speed_in_bytes_per_ms,
     size_t new_space_size) {
   if (scavenge_speed_in_bytes_per_ms == 0) {
     scavenge_speed_in_bytes_per_ms = kInitialScavengeSpeedInBytesPerMs;