Make lost context and error message callbacks on GpuControl go to client

blimp/client/feature/compositor/blimp_context_provider.cc

Index: blimp/client/feature/compositor/blimp_context_provider.cc
diff --git a/blimp/client/feature/compositor/blimp_context_provider.cc b/blimp/client/feature/compositor/blimp_context_provider.cc
index 43bdd770133a0ba3c88c914ce5a977977cdd1779..bfb6e8fb8cc83a05f002bb40ceb2c8264f647fbd 100644
--- a/blimp/client/feature/compositor/blimp_context_provider.cc
+++ b/blimp/client/feature/compositor/blimp_context_provider.cc
@@ -45,7 +45,7 @@ BlimpContextProvider::BlimpContextProvider(
       widget, gfx::Size(1, 1), nullptr /* share_context */, attribs_for_gles2,
       gfx::PreferDiscreteGpu, gpu::GLInProcessContextSharedMemoryLimits(),
       gpu_memory_buffer_manager, nullptr /* memory_limits */));
-  context_->SetContextLostCallback(
+  context_->GetImplementation()->SetLostContextCallback(
       base::Bind(&BlimpContextProvider::OnLostContext, base::Unretained(this)));
 }
 
@@ -128,7 +128,7 @@ void BlimpContextProvider::SetLostContextCallback(
 void BlimpContextProvider::OnLostContext() {
   DCHECK(context_thread_checker_.CalledOnValidThread());
   if (!lost_context_callback_.is_null())
-    base::ResetAndReturn(&lost_context_callback_).Run();
+    lost_context_callback_.Run();

[Wez, 2016/04/09 01:00:25]

Was this previously broken in clearing the callback, or do we now specifically
want to allow multiple OnLostContext() w/out SetLostContextCallback() calls
in-between?

[danakj, 2016/04/09 01:02:17]

The GpuControl will not call out more than once, so there's no need to guard
here. GLES2Impl DCHECKs this now.

[Wez, 2016/04/09 01:15:24]

Ah, so this way if that contract gets broken then higher levels will see
multiple lost context callbacks and barf accordingly. SGTM!

   if (gr_context_)
     gr_context_->abandonContext();
 }