cc: Add ResourceId validation checks at the time of AppendQuads.

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 f31cfd4da34e776878b87574f37a281741467f94..f3c6540707efd90652a5e1d3b19440fd429df13f 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -870,7 +870,7 @@ base::TimeTicks ResourceProvider::EstimatedUploadCompletionTime(
 
 ResourceProvider::Resource* ResourceProvider::GetResource(ResourceId id) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  // Try to differentiate GetResource with a bad id vs with no id.
+  // TODO(danakj): crbug.com/455931
   CHECK(id);
   ResourceMap::iterator it = resources_.find(id);
   CHECK(it != resources_.end());
@@ -2134,6 +2134,13 @@ GLint ResourceProvider::GetActiveTextureUnit(GLES2Interface* gl) {
   return active_unit;
 }
 
+void ResourceProvider::ValidateResource(ResourceId id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  CHECK(id);
+  ResourceMap::iterator it = resources_.find(id);
+  CHECK(it != resources_.end());
+}
+
 GLES2Interface* ResourceProvider::ContextGL() const {
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->ContextGL() : NULL;