Use a singleton 1x1 offscreen surface for all TextureImageTransportSurface instances.

content/common/gpu/gpu_channel_manager.cc

Index: content/common/gpu/gpu_channel_manager.cc
diff --git a/content/common/gpu/gpu_channel_manager.cc b/content/common/gpu/gpu_channel_manager.cc
index be60a19413468e7bca9090760b360de78b511651..1da6aecf2f3c82608fc57654592fc22c5d557c85 100644
--- a/content/common/gpu/gpu_channel_manager.cc
+++ b/content/common/gpu/gpu_channel_manager.cc
@@ -38,6 +38,10 @@ GpuChannelManager::GpuChannelManager(ChildThread* gpu_child_thread,
 
 GpuChannelManager::~GpuChannelManager() {
   gpu_channels_.clear();
+  if (default_offscreen_surface_.get()) {
+    default_offscreen_surface_->Destroy();
+    default_offscreen_surface_ = NULL;
+  }
 }
 
 gpu::gles2::ProgramCache* GpuChannelManager::program_cache() {
@@ -175,3 +179,11 @@ void GpuChannelManager::LoseAllContexts() {
 void GpuChannelManager::OnLoseAllContexts() {
   gpu_channels_.clear();
 }
+
+gfx::GLSurface* GpuChannelManager::GetDefaultOffscreenSurface() {
+  if (!default_offscreen_surface_.get()) {
+    default_offscreen_surface_ = gfx::GLSurface::CreateOffscreenGLSurface(
+        false, gfx::Size(1, 1));
+  }
+  return default_offscreen_surface_.get();
+}