gpu:: Remove GpuDataManagerObserver::OnVideoMemoryUsageStatsUpdate().

chrome/browser/task_manager/sampling/task_manager_impl.cc

Index: chrome/browser/task_manager/sampling/task_manager_impl.cc
diff --git a/chrome/browser/task_manager/sampling/task_manager_impl.cc b/chrome/browser/task_manager/sampling/task_manager_impl.cc
index afd1ca1514b513670949f16ce3f709cb9f5e3e30..aab3f46770eaf7fd4be07856bc040329d76adf91 100644
--- a/chrome/browser/task_manager/sampling/task_manager_impl.cc
+++ b/chrome/browser/task_manager/sampling/task_manager_impl.cc
@@ -50,7 +50,8 @@ TaskManagerImpl::TaskManagerImpl()
                      base::Unretained(this))),
       blocking_pool_runner_(GetBlockingPoolRunner()),
       shared_sampler_(new SharedSampler(blocking_pool_runner_)),
-      is_running_(false) {
+      is_running_(false),
+      weak_ptr_factory_(this) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   task_providers_.emplace_back(new BrowserProcessTaskProvider());
@@ -60,12 +61,9 @@ TaskManagerImpl::TaskManagerImpl()
   if (arc::IsArcAvailable())
     task_providers_.emplace_back(new ArcProcessTaskProvider());
 #endif  // defined(OS_CHROMEOS)
-
-  content::GpuDataManager::GetInstance()->AddObserver(this);
 }
 
 TaskManagerImpl::~TaskManagerImpl() {
-  content::GpuDataManager::GetInstance()->RemoveObserver(this);
 }
 
 // static
@@ -452,13 +450,6 @@ void TaskManagerImpl::TaskUnresponsive(Task* task) {
   NotifyObserversOnTaskUnresponsive(task->task_id());
 }
 
-void TaskManagerImpl::OnVideoMemoryUsageStatsUpdate(
-    const gpu::VideoMemoryUsageStats& gpu_memory_stats) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-
-  gpu_memory_stats_ = gpu_memory_stats;
-}
-
 // static
 void TaskManagerImpl::OnMultipleBytesReadUI(
     std::vector<BytesReadParam>* params) {
@@ -481,10 +472,18 @@ void TaskManagerImpl::OnMultipleBytesReadUI(
   }
 }
 
+void TaskManagerImpl::OnVideoMemoryUsageStatsUpdate(
+    const gpu::VideoMemoryUsageStats& gpu_memory_stats) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

[jbauman, 2017/04/20 21:35:02]

Won't this be called on the IO thread if it's run directly from the mojo
callback?

[sadrul, 2017/04/21 03:41:01]

Very nice. Good catch! Yes, you are right. I missed the detail that
GpuDataManagerImplPrivate has a ObserverListThreadSafe instead of an
ObserverList. Thanks for catching this!

+
+  gpu_memory_stats_ = gpu_memory_stats;
+}
+
 void TaskManagerImpl::Refresh() {
   if (IsResourceRefreshEnabled(REFRESH_TYPE_GPU_MEMORY)) {
-    content::GpuDataManager::GetInstance()->
-        RequestVideoMemoryUsageStatsUpdate();
+    content::GpuDataManager::GetInstance()->RequestVideoMemoryUsageStatsUpdate(
+        base::Bind(&TaskManagerImpl::OnVideoMemoryUsageStatsUpdate,
+                   weak_ptr_factory_.GetWeakPtr()));
   }
 
   for (auto& groups_itr : task_groups_by_proc_id_) {