content: Add SharedBitmap MemoryDumpProvider implementation.

content/common/host_shared_bitmap_manager.cc

Index: content/common/host_shared_bitmap_manager.cc
diff --git a/content/common/host_shared_bitmap_manager.cc b/content/common/host_shared_bitmap_manager.cc
index b95820c2f32c44867d7b3abba5f2b05d70f1d00d..3e499d648d03fc0666186a4f8e9ecffbceb9093f 100644
--- a/content/common/host_shared_bitmap_manager.cc
+++ b/content/common/host_shared_bitmap_manager.cc
@@ -6,6 +6,10 @@
 
 #include "base/lazy_instance.h"
 #include "base/memory/ref_counted.h"
+#include "base/strings/stringprintf.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "content/common/view_messages.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -50,6 +54,8 @@ class HostSharedBitmap : public cc::SharedBitmap {
   HostSharedBitmapManager* manager_;
 };
 
+const char kMemoryAllocatorName[] = "sharedbitmap";
+
 }  // namespace
 
 base::LazyInstance<HostSharedBitmapManager> g_shared_memory_manager =
@@ -90,9 +96,15 @@ void HostSharedBitmapManagerClient::ChildDeletedSharedBitmap(
   owned_bitmaps_.erase(id);
 }
 
-HostSharedBitmapManager::HostSharedBitmapManager() {}
+HostSharedBitmapManager::HostSharedBitmapManager() {
+  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
+      this);

[Primiano Tucci (use gerrit), 2015/04/28 21:40:06]

I think you want a task_runner (IIRC the HostSBM is in the RendererMesageFilter
which lives on the IO?).
If the ctor already happens on the IO, just use TaskRunnerHandler::Get()

[reveman, 2015/04/29 01:45:58]

This is a singleton. See HostSharedBitmapManager::current().

+}
+
 HostSharedBitmapManager::~HostSharedBitmapManager() {
   DCHECK(handle_map_.empty());
+  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
+      this);

[Primiano Tucci (use gerrit), 2015/04/28 21:40:06]

Hmm if you unregister you should specify a task_runner in the registration,
otherwise you'll hit a CHECK in the MDM.
The rational is: you can't declare that you are fine being called on any thread
(no task_runner arg) and at the same time unregister, otherwise the MDM could
call you while you unregister on a different thread.
IN essence, no-affinity (no taskrunner) is safe only for MDPs that are
singletons.

[reveman, 2015/04/29 01:45:58]

Makes sense. I moved RegisterDumpProvider() call to
BrowserMainLoop::MainMessageLoopStart to make this less confusing.

 }
 
 HostSharedBitmapManager* HostSharedBitmapManager::current() {
@@ -146,6 +158,29 @@ scoped_ptr<cc::SharedBitmap> HostSharedBitmapManager::GetSharedBitmapFromId(
       static_cast<uint8*>(data->memory->memory()), data, id, nullptr));
 }
 
+bool HostSharedBitmapManager::OnMemoryDump(
+    base::trace_event::ProcessMemoryDump* pmd) {
+  base::AutoLock lock(lock_);
+
+  for (const auto& bitmap_it : handle_map_) {
+    std::string heap_name;
+
+    for (size_t i = 0; i < sizeof(bitmap_it.first.name); ++i)
+      base::StringAppendF(&heap_name, "%02x", bitmap_it.first.name[i]);
+
+    base::trace_event::MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(
+        base::StringPrintf("%s/%s", kMemoryAllocatorName, heap_name.c_str()));
+    if (!dump)
+      return false;
+
+    dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameOuterSize,
+                    base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                    bitmap_it.second->buffer_size);
+  }
+
+  return true;
+}
+
 void HostSharedBitmapManager::ChildAllocatedSharedBitmap(
     size_t buffer_size,
     const base::SharedMemoryHandle& handle,