Implement native GMB backbuffers in the GLES2 Command Decoder.

gpu/command_buffer/tests/gl_manager.cc

Index: gpu/command_buffer/tests/gl_manager.cc
diff --git a/gpu/command_buffer/tests/gl_manager.cc b/gpu/command_buffer/tests/gl_manager.cc
index cf07ea04123d7a67aa173ce663965fb7910705c9..8472a9b53e04b4660b244be8aadfde97c3373b28 100644
--- a/gpu/command_buffer/tests/gl_manager.cc
+++ b/gpu/command_buffer/tests/gl_manager.cc
@@ -185,7 +185,10 @@ GLManager::Options::Options()
       context_lost_allowed(false),
       context_type(gles2::CONTEXT_TYPE_OPENGLES2),
       force_shader_name_hashing(false),
-      multisampled(false) {}
+      multisampled(false),
+      backbuffer_alpha(true),
+      image_factory(nullptr),
+      enable_arb_texture_rectangle(false) {}
 
 GLManager::GLManager()
     : sync_point_manager_(nullptr),
@@ -287,16 +290,25 @@ void GLManager::InitializeWithCommandLine(
   attribs.context_type = options.context_type;
   attribs.samples = options.multisampled ? 4 : 0;
   attribs.sample_buffers = options.multisampled ? 1 : 0;
+  attribs.alpha_size = options.backbuffer_alpha ? 8 : 0;
+  attribs.should_use_native_gmb_for_backbuffer =
+      options.image_factory != nullptr;
 
   if (!context_group) {
     GpuDriverBugWorkarounds gpu_driver_bug_workaround(&command_line);
     scoped_refptr<gles2::FeatureInfo> feature_info =
         new gles2::FeatureInfo(command_line, gpu_driver_bug_workaround);
+    if (options.enable_arb_texture_rectangle) {
+      gles2::FeatureInfo::FeatureFlags& flags =
+          const_cast<gles2::FeatureInfo::FeatureFlags&>(
+              feature_info->feature_flags());
+      flags.arb_texture_rectangle = true;
+    }
     context_group = new gles2::ContextGroup(
         gpu_preferences_, mailbox_manager_.get(), NULL,
         new gpu::gles2::ShaderTranslatorCache(gpu_preferences_),
         new gpu::gles2::FramebufferCompletenessCache, feature_info,
-        options.bind_generates_resource);
+        options.bind_generates_resource, options.image_factory);
   }
 
   decoder_.reset(::gpu::gles2::GLES2Decoder::Create(context_group));