Use EXT_robustness where available on GLES2 platforms to detect and respond to resets of the graphi…

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 12cda4b48269b31041b9e56a18f7c705223ab64c..e83be95cfea4af7d5d37b64088364984dd75caac 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -279,14 +279,15 @@ void GpuCommandBufferStub::Destroy() {
     delayed_echos_.pop_front();
   }
 
+  bool have_context = false;
   if (decoder_.get())
-    decoder_->MakeCurrent();
+    have_context = decoder_->MakeCurrent();
   FOR_EACH_OBSERVER(DestructionObserver,
                     destruction_observers_,
                     OnWillDestroyStub(this));
 
   if (decoder_.get()) {
-    decoder_->Destroy(true);
+    decoder_->Destroy(have_context);
     decoder_.reset();
   }