Adding discardable memory dump provider.

content/child/child_discardable_shared_memory_manager.cc

Index: content/child/child_discardable_shared_memory_manager.cc
diff --git a/content/child/child_discardable_shared_memory_manager.cc b/content/child/child_discardable_shared_memory_manager.cc
index 961733170d578d2a5e23057504a4f822be513589..f3533dad37d97c2a036c8a4241bc6ce22b8621b5 100644
--- a/content/child/child_discardable_shared_memory_manager.cc
+++ b/content/child/child_discardable_shared_memory_manager.cc
@@ -13,6 +13,8 @@
 #include "base/process/memory.h"
 #include "base/process/process_metrics.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/trace_event.h"
 #include "content/common/child_process_messages.h"
 
@@ -27,6 +29,8 @@ const size_t kAllocationSize = 32 * 1024 * 1024;
 const size_t kAllocationSize = 4 * 1024 * 1024;
 #endif
 
+const char kMemoryDumperFriendlyName[] = "Discardable";
+
 // Global atomic to generate unique discardable shared memory IDs.
 base::StaticAtomicSequenceNumber g_next_discardable_shared_memory_id;
 
@@ -82,10 +86,16 @@ void SendDeletedDiscardableSharedMemoryMessage(
 
 ChildDiscardableSharedMemoryManager::ChildDiscardableSharedMemoryManager(
     ThreadSafeSender* sender)
-    : heap_(base::GetPageSize()), sender_(sender) {
+    : MemoryDumpProvider(base::ThreadTaskRunnerHandle::Get()),
+      heap_(base::GetPageSize()),
+      sender_(sender) {
+  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
+      this);
 }
 
 ChildDiscardableSharedMemoryManager::~ChildDiscardableSharedMemoryManager() {
+  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
+      this);
   // TODO(reveman): Determine if this DCHECK can be enabled. crbug.com/430533
   // DCHECK_EQ(heap_.GetSize(), heap_.GetSizeOfFreeLists());
   if (heap_.GetSize())
@@ -189,6 +199,15 @@ ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
   return make_scoped_ptr(new DiscardableMemoryImpl(this, new_span.Pass()));
 }
 
+bool ChildDiscardableSharedMemoryManager::DumpInto(
+    base::trace_event::ProcessMemoryDump* pmd) {
+  return heap_.DumpMemoryStatisticsInto(pmd);
+}
+
+const char* ChildDiscardableSharedMemoryManager::GetFriendlyName() const {
+  return kMemoryDumperFriendlyName;
+}
+
 void ChildDiscardableSharedMemoryManager::ReleaseFreeMemory() {
   base::AutoLock lock(lock_);