Add lock around modification of HostSharedBitmapManagerClient::owned_bitmaps_

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 f913dba71bf0b5b31916fed5e5e431846837a4ac..2ebeb294e5c0729c2656fb95faf8e788a8e5bdc5 100644
--- a/content/common/host_shared_bitmap_manager.cc
+++ b/content/common/host_shared_bitmap_manager.cc
@@ -63,6 +63,7 @@ HostSharedBitmapManagerClient::HostSharedBitmapManagerClient(
 }
 
 HostSharedBitmapManagerClient::~HostSharedBitmapManagerClient() {
+  base::AutoLock lock(lock_);

[piman, 2015/11/24 03:00:37]

nit: I think you don't need this one (only 1 thread can call this at a time).

   for (const auto& id : owned_bitmaps_)
     manager_->ChildDeletedSharedBitmap(id);
 }
@@ -74,7 +75,10 @@ void HostSharedBitmapManagerClient::AllocateSharedBitmapForChild(
     base::SharedMemoryHandle* shared_memory_handle) {
   manager_->AllocateSharedBitmapForChild(process_handle, buffer_size, id,
                                          shared_memory_handle);
-  owned_bitmaps_.insert(id);
+  if (*shared_memory_handle != base::SharedMemory::NULLHandle()) {
+    base::AutoLock lock(lock_);
+    owned_bitmaps_.insert(id);
+  }
 }
 
 void HostSharedBitmapManagerClient::ChildAllocatedSharedBitmap(
@@ -82,14 +86,20 @@ void HostSharedBitmapManagerClient::ChildAllocatedSharedBitmap(
     const base::SharedMemoryHandle& handle,
     base::ProcessHandle process_handle,
     const cc::SharedBitmapId& id) {
-  manager_->ChildAllocatedSharedBitmap(buffer_size, handle, process_handle, id);
-  owned_bitmaps_.insert(id);
+  if (manager_->ChildAllocatedSharedBitmap(buffer_size, handle, process_handle,
+                                           id)) {
+    base::AutoLock lock(lock_);
+    owned_bitmaps_.insert(id);
+  }
 }
 
 void HostSharedBitmapManagerClient::ChildDeletedSharedBitmap(
     const cc::SharedBitmapId& id) {
   manager_->ChildDeletedSharedBitmap(id);
-  owned_bitmaps_.erase(id);
+  {
+    base::AutoLock lock(lock_);
+    owned_bitmaps_.erase(id);
+  }
 }
 
 HostSharedBitmapManager::HostSharedBitmapManager() {}
@@ -176,14 +186,14 @@ bool HostSharedBitmapManager::OnMemoryDump(
   return true;
 }
 
-void HostSharedBitmapManager::ChildAllocatedSharedBitmap(
+bool HostSharedBitmapManager::ChildAllocatedSharedBitmap(
     size_t buffer_size,
     const base::SharedMemoryHandle& handle,
     base::ProcessHandle process_handle,
     const cc::SharedBitmapId& id) {
   base::AutoLock lock(lock_);
   if (handle_map_.find(id) != handle_map_.end())
-    return;
+    return false;
   scoped_refptr<BitmapData> data(
       new BitmapData(process_handle, buffer_size));
 
@@ -195,8 +205,9 @@ void HostSharedBitmapManager::ChildAllocatedSharedBitmap(
   data->memory =
       make_scoped_ptr(new base::SharedMemory(handle, false));
 #endif
- data->memory->Map(data->buffer_size);
- data->memory->Close();
+  data->memory->Map(data->buffer_size);
+  data->memory->Close();
+  return true;
 }
 
 void HostSharedBitmapManager::AllocateSharedBitmapForChild(