cc: Changes to use GL API for GpuMemoryBuffers

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 657e72f9d52b88cddb8d6b6d70697fc2ccfc2f0d..3ef83ca3a32c8f9957171d7b7eb464d2c15b226d 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "base/basictypes.h"
+#include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram.h"
@@ -14,6 +15,7 @@
 #include "base/stringprintf.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/base/math_util.h"
+#include "cc/base/switches.h"
 #include "cc/base/util.h"
 #include "cc/debug/debug_rect_history.h"
 #include "cc/debug/frame_rate_counter.h"
@@ -1340,6 +1342,10 @@ bool LayerTreeHostImpl::InitializeRenderer(
   if (!resource_provider)
     return false;
 
+  if (CommandLine::ForCurrentProcess()->HasSwitch(

[jamesr, 2013/04/25 22:50:46]

I don't think this is a good way to plumb this setting in since it's global for
the process but not necessarily something you want set the same way for every
compositor instance in that process.  Instead, what we normally do is add an
entry to cc::LayerTreeSettings and have code outside cc:: (that's aware of the
process model in use) map the command line flag to the setting.

[kaanb1, 2013/04/25 23:55:05]

Done.

+      cc::switches::kUseGpuMemoryBuffers))
+    resource_provider->SetUseGpuMemoryBuffers(true);
+
   if (settings_.impl_side_painting) {
     tile_manager_.reset(new TileManager(this,
                                         resource_provider.get(),