Make GetMallocUsages to check only the default process heap.

BUG=671459
TBR=avi@chromium.org

Review-Url: https://codereview.chromium.org/2565273002
Cr-Commit-Position: refs/heads/master@{#437819}

content/renderer/render_thread_impl.cc

@@ -1809,31 +1809,20 @@ void RenderThreadImpl::OnProcessPurgeAndSuspend() {
 namespace {
 
 static size_t GetMallocUsage() {
-  DWORD number_of_heaps = ::GetProcessHeaps(0, NULL);
-  if (number_of_heaps <= 0)
+  // Only checks the default process heap.
+  HANDLE heap = ::GetProcessHeap();
+  if (heap == NULL)
     return 0;
-
+  if (!::HeapLock(heap))
+    return 0 ;
   size_t malloc_usage = 0;
-  std::unique_ptr<HANDLE[]> heaps(new HANDLE[number_of_heaps]);
-  // If some heaps were gone between the first GetProcessHeaps and here,
-  // GetProcessHeaps obtains small number of heaps.
-  // If some new heaps were available between the first GetProcessHeaps and
-  // here, GetProcessHeaps returns larger number than number_of_heaps.
-  // So we need to see min(number_of_obtained_heaps, number_of_heaps).
-  DWORD number_of_obtained_heaps =
-      ::GetProcessHeaps(number_of_heaps, heaps.get());
-  for (size_t i = 0; i < number_of_heaps && i < number_of_obtained_heaps; i++) {
-    PROCESS_HEAP_ENTRY heap_entry;
-    ::HeapLock(heaps[i]);
-    heap_entry.lpData = NULL;
-    while (::HeapWalk(heaps[i], &heap_entry) != 0) {
-      if (heap_entry.lpData == heaps.get())
-        continue;
-      if ((heap_entry.wFlags & PROCESS_HEAP_ENTRY_BUSY) != 0)
-        malloc_usage += heap_entry.cbData;
-    }
-    ::HeapUnlock(heaps[i]);
+  PROCESS_HEAP_ENTRY heap_entry;
+  heap_entry.lpData = NULL;
+  while (::HeapWalk(heap, &heap_entry) != 0) {
+    if ((heap_entry.wFlags & PROCESS_HEAP_ENTRY_BUSY) != 0)
+      malloc_usage += heap_entry.cbData;
   }
+  ::HeapUnlock(heap);
   return malloc_usage;
 }