cc: Free gpu resources when we are invisible or TM is oom.

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index 5428c940150edecf78004c6f99223d5b9b18d474..43f75f3f7417b0349f90183e89a4bbcb29e5c676 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -2151,4 +2151,28 @@ class GrContext* ResourceProvider::GrContext(bool worker_context) const {
   return context_provider ? context_provider->GrContext() : NULL;
 }
 
+void ResourceProvider::FreeGrResources() {
+  if (!output_surface_)
+    return;
+
+  ContextProvider* context_provider =
+      output_surface_->worker_context_provider();
+  if (!context_provider)
+    return;
+
+  // The context lock must be held while accessing the context on a
+  // worker thread.
+  base::AutoLock context_lock(*context_provider->GetLock());
+
+  // Allow context to bind to current thread.
+  context_provider->DetachFromThread();
+
+  class GrContext* gr_context = context_provider->GrContext();
+  DCHECK(gr_context);
+  gr_context->freeGpuResources();
+
+  // Allow context to bind to other threads.
+  context_provider->DetachFromThread();
+}
+
 }  // namespace cc