[tracing] Introduce MemoryDumpArgs to enable light and heavy dumps

base/trace_event/memory_dump_provider.h

Index: base/trace_event/memory_dump_provider.h
diff --git a/base/trace_event/memory_dump_provider.h b/base/trace_event/memory_dump_provider.h
index 6e6551cc03988df685fb72d2e489e626ba583ab3..fbd58627ca3e7f4bebc1659f2397e63327951ed7 100644
--- a/base/trace_event/memory_dump_provider.h
+++ b/base/trace_event/memory_dump_provider.h
@@ -13,6 +13,14 @@ namespace trace_event {
 
 class ProcessMemoryDump;
 
+struct MemoryDumpArgs {

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

Could you please explain the relationship between MemoryDumpArgs (added in this
patch) and MemoryDumpRequestArgs (existing class:
https://code.google.com/p/chromium/codesearch#chromium/src/base/trace_event/m...
)? I'm wondering whether they should be the same thing.

[ssid, 2015/07/31 15:14:33]

Hm, the MemoryDumpRequestArgs is used to request a global dump, contains what
type of dump is to be taken to the manager. This args is to tell the dump
provider what kind of dump to take. I can't merge both since the providers need
not know what triggered the dump or the global dump guid.

The PERIODIC_INTERVAL_WITH_MMAPS will be removed and maybe MemoryDumpArgs should
be a part of MemoryDumpRequest args for requesting.

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

OK, this makes sense. Thanks for the explanation.

+  enum LevelOfDetail { LEVEL_OF_DETAIL_LOW, LEVEL_OF_DETAIL_HIGH };
+
+  explicit MemoryDumpArgs(const LevelOfDetail level) : level_of_detail(level) {}
+
+  LevelOfDetail level_of_detail;

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

const?

[ssid, 2015/07/31 15:14:33]

Done.

+};
+
 // The contract interface that memory dump providers must implement.
 class BASE_EXPORT MemoryDumpProvider {
  public:
@@ -21,7 +29,8 @@ class BASE_EXPORT MemoryDumpProvider {
   // false if something went wrong and the dump should be considered invalid.
   // (Note, the MemoryDumpManager has a fail-safe logic which will disable the
   // MemoryDumpProvider for the entire trace session if it fails consistently).
-  virtual bool OnMemoryDump(ProcessMemoryDump* pmd) = 0;
+  virtual bool OnMemoryDump(const MemoryDumpArgs& args,
+                            ProcessMemoryDump* pmd) = 0;
 
  protected:
   MemoryDumpProvider() {}