ozone: Introduce ClientPixmap and ClientPixmapFactory for non-GPU processes.

content/child/child_gpu_memory_buffer_manager.cc

Index: content/child/child_gpu_memory_buffer_manager.cc
diff --git a/content/child/child_gpu_memory_buffer_manager.cc b/content/child/child_gpu_memory_buffer_manager.cc
index 0e1c312ad1cc91237d368457b5e8201d6fd8f505..d294dce552beb94c04df7fb6252def5d7bcbe4a8 100644
--- a/content/child/child_gpu_memory_buffer_manager.cc
+++ b/content/child/child_gpu_memory_buffer_manager.cc
@@ -7,6 +7,10 @@
 #include "content/common/child_process_messages.h"
 #include "content/common/gpu/client/gpu_memory_buffer_impl.h"
 
+#if defined(USE_OZONE)
+#include "ui/ozone/public/native_pixmap_client.h"
+#endif
+
 namespace content {
 namespace {
 
@@ -40,6 +44,10 @@ ChildGpuMemoryBufferManager::AllocateGpuMemoryBuffer(
                "height",
                size.height());
 
+#if defined(USE_OZONE)
+  ui::NativePixmapClient::InitializeIfNeeded();

[dshwang, 2015/06/03 14:11:51]

As you mentioned "The processes that want one will create one, and the processes
that don't need one won't.", this interface is initialized very lazily when it's
needed for Renderer.

[spang, 2015/06/05 19:21:53]

Lazy initialization leads to unpredictable initialization order.

Please do it eagerly and only once.

[reveman, 2015/06/05 20:26:06]

The MacOSX equivalent to NativePixmap is IOSurface and the child process wide
initialization of that is done in content/app/content_main_runner.cc. See
IOSurfaceManager::SetInstance. I think it would be best to do this
NativePixmapClient initialization at the same place.

[dshwang, 2015/06/08 11:15:14]

Done. Initialize it in render_thread_impl.cc, not content_main_runner.cc,
because gpu process doesn't need it.
btw, the interface doesn't use global or filescope object, so IMO this lazy
initialization isn't related to unpredictable initialization order.

+#endif
+
   gfx::GpuMemoryBufferHandle handle;
   IPC::Message* message = new ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer(
       size.width(), size.height(), format, usage, &handle);