[tracing] Introduce MemoryDumpArgs to enable light and heavy dumps

base/trace_event/malloc_dump_provider.cc

Index: base/trace_event/malloc_dump_provider.cc
diff --git a/base/trace_event/malloc_dump_provider.cc b/base/trace_event/malloc_dump_provider.cc
index 3e593b02897cb9ce8477765858469f5c4160d402..224b905e4f1ab8f052727c55c45928860eaa4dbb 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -28,7 +28,8 @@ MallocDumpProvider::~MallocDumpProvider() {
 
 // Called at trace dump point time. Creates a snapshot the memory counters for
 // the current process.
-bool MallocDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
+bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,

[petrcermak, 2015/07/31 13:23:01]

Is there a reason why you put the args first as the first argument?

[ssid, 2015/07/31 15:14:32]

Yes according to code style, the input args should be placed before the output
ones.

[petrcermak, 2015/08/03 10:12:35]

Acknowledged.

+                                      ProcessMemoryDump* pmd) {
   struct mallinfo info = mallinfo();
   DCHECK_GE(info.arena + info.hblkhd, info.uordblks);