Implement blacklist's force GPU capability in dual GPU machines.

content/browser/gpu/gpu_util.cc

Index: content/browser/gpu/gpu_util.cc
===================================================================
--- content/browser/gpu/gpu_util.cc	(revision 156326)
+++ content/browser/gpu/gpu_util.cc	(working copy)
@@ -30,11 +30,6 @@
 const char kGpuFeatureNameAll[] = "all";
 const char kGpuFeatureNameUnknown[] = "unknown";
 
-const char kGpuSwitchingNameAutomatic[] = "automatic";
-const char kGpuSwitchingNameForceIntegrated[] = "force_integrated";
-const char kGpuSwitchingNameForceDiscrete[] = "force_discrete";
-const char kGpuSwitchingNameUnknown[] = "unknown";
-
 enum GpuFeatureStatus {
     kGpuFeatureEnabled = 0,
     kGpuFeatureBlacklisted = 1,
@@ -141,15 +136,28 @@
 
 GpuSwitchingOption StringToGpuSwitchingOption(
     const std::string& switching_string) {
-  if (switching_string == kGpuSwitchingNameAutomatic)
-    return content::GPU_SWITCHING_AUTOMATIC;
-  if (switching_string == kGpuSwitchingNameForceIntegrated)
-    return content::GPU_SWITCHING_FORCE_INTEGRATED;
-  if (switching_string == kGpuSwitchingNameForceDiscrete)
-    return content::GPU_SWITCHING_FORCE_DISCRETE;
-  return content::GPU_SWITCHING_UNKNOWN;
+  if (switching_string == kGpuSwitchingOptionNameAutomatic)
+    return content::GPU_SWITCHING_OPTION_AUTOMATIC;
+  if (switching_string == kGpuSwitchingOptionNameForceIntegrated)
+    return content::GPU_SWITCHING_OPTION_FORCE_INTEGRATED;
+  if (switching_string == kGpuSwitchingOptionNameForceDiscrete)
+    return content::GPU_SWITCHING_OPTION_FORCE_DISCRETE;
+  return content::GPU_SWITCHING_OPTION_UNKNOWN;
 }
 
+std::string GpuSwitchingOptionToString(GpuSwitchingOption option) {
+  switch (option) {
+    case content::GPU_SWITCHING_OPTION_AUTOMATIC:
+      return kGpuSwitchingOptionNameAutomatic;
+    case content::GPU_SWITCHING_OPTION_FORCE_INTEGRATED:
+      return kGpuSwitchingOptionNameForceIntegrated;
+    case content::GPU_SWITCHING_OPTION_FORCE_DISCRETE:
+      return kGpuSwitchingOptionNameForceDiscrete;
+    default:
+      return "unknown";
+  }
+}
+
 void UpdateStats(const GpuBlacklist* blacklist,
                  uint32 blacklisted_features) {
   uint32 max_entry_id = blacklist->max_entry_id();