Reland of [Tracing] Adjust allocation register size for low-end devices

base/trace_event/heap_profiler_allocation_register.cc

Index: base/trace_event/heap_profiler_allocation_register.cc
diff --git a/base/trace_event/heap_profiler_allocation_register.cc b/base/trace_event/heap_profiler_allocation_register.cc
index 37647eefbbb1246bea852f86adfe6843903801ee..292015359e9f88f6e0a8f76c3ea2bf2ede884ce3 100644
--- a/base/trace_event/heap_profiler_allocation_register.cc
+++ b/base/trace_event/heap_profiler_allocation_register.cc
@@ -10,10 +10,14 @@ namespace base {
 namespace trace_event {
 
 AllocationRegister::AllocationRegister()
-    // Reserve enough address space to store |kNumCells| entries if necessary,
+    : AllocationRegister(kNumBuckets * kNumCellsPerBucket) {}
+
+AllocationRegister::AllocationRegister(uint32_t num_cells)
+    // Reserve enough address space to store |num_cells_| entries if necessary,
     // with a guard page after it to crash the program when attempting to store
     // more entries.
-    : cells_(static_cast<Cell*>(AllocateVirtualMemory(kNumCells *
+    : num_cells_(num_cells),
+      cells_(static_cast<Cell*>(AllocateVirtualMemory(num_cells_ *
                                                       sizeof(Cell)))),
       buckets_(static_cast<CellIndex*>(
           AllocateVirtualMemory(kNumBuckets * sizeof(CellIndex)))),
@@ -23,9 +27,10 @@ AllocationRegister::AllocationRegister()
       free_list_(0),
       next_unused_cell_(1) {}
 
+

[Primiano Tucci (use gerrit), 2015/12/18 10:40:09]

nit: extra newline?

 AllocationRegister::~AllocationRegister() {
   FreeVirtualMemory(buckets_, kNumBuckets * sizeof(CellIndex));
-  FreeVirtualMemory(cells_, kNumCells * sizeof(Cell));
+  FreeVirtualMemory(cells_, num_cells_ * sizeof(Cell));
 }
 
 void AllocationRegister::Insert(void* address,
@@ -144,7 +149,7 @@ AllocationRegister::CellIndex AllocationRegister::GetFreeCell() {
   // the simplest solution is to just allocate a humongous chunk of address
   // space.
 
-  DCHECK_LT(next_unused_cell_, kNumCells + 1);
+  DCHECK_LT(next_unused_cell_, num_cells_ + 1);
 
   return idx;
 }