Add cc::SharedBitmap::shared_memory_handle()

components/viz/display_compositor/host_shared_bitmap_manager.cc

Index: components/viz/display_compositor/host_shared_bitmap_manager.cc
diff --git a/components/viz/display_compositor/host_shared_bitmap_manager.cc b/components/viz/display_compositor/host_shared_bitmap_manager.cc
index d781c9439cbe0cd1ae7d5c2b02fec0f63245f994..87febf9e95247c3174c4816e137513b8ef047499 100644
--- a/components/viz/display_compositor/host_shared_bitmap_manager.cc
+++ b/components/viz/display_compositor/host_shared_bitmap_manager.cc
@@ -51,6 +51,13 @@ class HostSharedBitmap : public cc::SharedBitmap {
       manager_->FreeSharedMemoryFromMap(id());
   }
 
+  // cc::SharedBitmap:
+  base::SharedMemoryHandle shared_memory_handle() const override {
+    if (!bitmap_data_->memory)

[danakj, 2017/05/31 16:10:31]

When can this be null?

[hajimehoshi, 2017/06/01 04:47:58]

When this is created from  HostSharedBitmapManager::AllocateSharedBitmap: the
comment says that "Bitmaps allocated in host don't need to be shared to other
processes, so allocate them with new instead.".

+      return base::SharedMemoryHandle();
+    return bitmap_data_->memory->handle();
+  }
+
  private:
   scoped_refptr<BitmapData> bitmap_data_;
   HostSharedBitmapManager* manager_;