Revert 173248, broke building on the official chrome/win bot:

content/gpu/gpu_info_collector_mac.mm

Index: content/gpu/gpu_info_collector_mac.mm
===================================================================
--- content/gpu/gpu_info_collector_mac.mm	(revision 173266)
+++ content/gpu/gpu_info_collector_mac.mm	(working copy)
@@ -158,8 +158,9 @@
 
 namespace gpu_info_collector {
 
-bool CollectContextGraphicsInfo(content::GPUInfo* gpu_info) {
+bool CollectGraphicsInfo(content::GPUInfo* gpu_info) {
   DCHECK(gpu_info);
+  *gpu_info = content::GPUInfo();
 
   TRACE_EVENT0("gpu", "gpu_info_collector::CollectGraphicsInfo");
 
@@ -169,7 +170,7 @@
   return CollectGraphicsInfoGL(gpu_info);
 }
 
-bool CollectBasicGraphicsInfo(content::GPUInfo* gpu_info) {
+bool CollectPreliminaryGraphicsInfo(content::GPUInfo* gpu_info) {
   DCHECK(gpu_info);
 
   std::string model_name;
@@ -183,6 +184,10 @@
   return CollectPCIVideoCardInfo(gpu_info);
 }
 
+bool CollectVideoCardInfo(content::GPUInfo* gpu_info) {
+  return CollectPreliminaryGraphicsInfo(gpu_info);
+}
+
 bool CollectDriverInfoGL(content::GPUInfo* gpu_info) {
   DCHECK(gpu_info);
 
@@ -198,9 +203,4 @@
   return true;
 }
 
-void MergeGPUInfo(content::GPUInfo* basic_gpu_info,
-                  const content::GPUInfo& context_gpu_info) {
-  MergeGPUInfoGL(basic_gpu_info, context_gpu_info);
-}
-
 }  // namespace gpu_info_collector