gpu in-memory program cache implementation with a memory limit + lru eviction.

content/common/gpu/gpu_command_buffer_stub.cc

Index: content/common/gpu/gpu_command_buffer_stub.cc
diff --git a/content/common/gpu/gpu_command_buffer_stub.cc b/content/common/gpu/gpu_command_buffer_stub.cc
index 6a281e4169071af8cb204994d542fb7c4e9c14b2..12cda4b48269b31041b9e56a18f7c705223ab64c 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -376,6 +376,11 @@ void GpuCommandBufferStub::OnInitialize(
     return;
   }
 
+  if (!context_group_->has_program_cache()) {
+    context_group_->set_program_cache(
+        channel_->gpu_channel_manager()->program_cache());
+  }
+
   // Initialize the decoder with either the view or pbuffer GLContext.
   if (!decoder_->Initialize(surface_,
                             context_,