cc: Add flag to specify to ResourceProvider to always use GMBs

cc/output/renderer_settings.cc

Index: cc/output/renderer_settings.cc
diff --git a/cc/output/renderer_settings.cc b/cc/output/renderer_settings.cc
index db961c91edc822c5b4395ce60fa50806486e85f0..27a644e6e441edd039735b3fc8891d612a5bdd37 100644
--- a/cc/output/renderer_settings.cc
+++ b/cc/output/renderer_settings.cc
@@ -21,7 +21,8 @@ RendererSettings::RendererSettings()
       refresh_rate(60.0),
       highp_threshold_min(0),
       use_rgba_4444_textures(false),
-      texture_id_allocation_chunk_size(64) {}
+      texture_id_allocation_chunk_size(64),
+      use_gpu_memory_buffers_by_default(false) {}
 
 RendererSettings::~RendererSettings() {
 }