Enable sync allocation of GpuMemoryBuffers from the browser process.

content/common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc

Index: content/common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc
diff --git a/content/common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc b/content/common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc
index fe2681bf051df7b4e5efe3aef6b7db461204fe2e..2a1a147dd807297dc2a084d274d0666b791e51e1 100644
--- a/content/common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc
+++ b/content/common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc
@@ -46,6 +46,21 @@ void GpuMemoryBufferImplOzoneNativeBuffer::AllocateOzoneNativeBufferForChildId(
 }
 
 // static
+gfx::GpuMemoryBufferHandle
+GpuMemoryBufferImplOzoneNativeBuffer::AllocateOzoneNativeBufferForBrowser(
+    const gfx::Size& size,
+    unsigned internalformat,
+    unsigned usage) {
+  gfx::GpuMemoryBufferHandle handle;
+  // +1 ensures we always get non-zero IDs.

[reveman, 2014/09/04 19:43:31]

Except when it wraps around. Consider adding a GetNextBufferId utility function
that calls g_next_buffer_id.GetNext() multiple times if necessary.

Btw, why does this need to be a non-zero?

[alexst (slow to review), 2014/09/04 21:14:47]

This is copy/pasted from just above in this file. I don't think there is any
hard reason why it couldn't be zero other than by convention of zero being a
null object.

[reveman, 2014/09/04 22:37:24]

There's already an explicit NULL value for GpuMemoryBufferHandle. I think we
should clean this up by making 0 a valid id. You can do that in a separate patch
or in this patch. Whatever you prefer.

[alexst (slow to review), 2014/09/05 02:04:53]

Done.

+  handle.global_id.primary_id = g_next_buffer_id.GetNext() + 1;
+  handle.global_id.secondary_id = 0;
+  handle.type = gfx::OZONE_NATIVE_BUFFER;
+  return GpuMemoryBufferFactoryHost::GetInstance()->CreateGpuMemoryBufferSync(
+      handle, size, internalformat, usage);
+}
+
+// static
 bool GpuMemoryBufferImplOzoneNativeBuffer::IsFormatSupported(
     unsigned internalformat) {
   switch (internalformat) {