Add UMA histogram to determine how often Stage3D could be used.

webkit/plugins/ppapi/ppapi_plugin_instance.cc

Index: webkit/plugins/ppapi/ppapi_plugin_instance.cc
diff --git a/webkit/plugins/ppapi/ppapi_plugin_instance.cc b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
index 36569266fbcc26a230ea6c32eafaa6ab587505c1..29d724b303be004b2eb1a929272e5beeeb4654f9 100644
--- a/webkit/plugins/ppapi/ppapi_plugin_instance.cc
+++ b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
@@ -29,6 +29,7 @@
 #include "ppapi/c/ppp_mouse_lock.h"
 #include "ppapi/c/private/pp_content_decryptor.h"
 #include "ppapi/c/private/ppp_instance_private.h"
+#include "ppapi/shared_impl/ppapi_preferences.h"
 #include "ppapi/shared_impl/ppb_input_event_shared.h"
 #include "ppapi/shared_impl/ppb_url_util_shared.h"
 #include "ppapi/shared_impl/ppb_view_shared.h"
@@ -96,6 +97,7 @@
 
 #if defined(OS_WIN)
 #include "base/metrics/histogram.h"
+#include "base/win/windows_version.h"
 #include "skia/ext/platform_canvas.h"
 #include "ui/gfx/codec/jpeg_codec.h"
 #include "ui/gfx/gdi_util.h"
@@ -533,6 +535,37 @@ void PluginInstance::InstanceCrashed() {
   delegate()->PluginCrashed(this);
 }
 
+static void SetGPUHistogram(const ::ppapi::Preferences& prefs,
+                            const std::vector<std::string>& arg_names,
+                            const std::vector<std::string>& arg_values) {
+  // Calculate a histogram to let us determine how likely people are to try to
+  // run Stage3D content on machines that have it blacklisted.
+#if defined(OS_WIN)
+  bool needs_gpu = false;
+  bool is_xp = base::win::GetVersion() <= base::win::VERSION_XP;
+
+  for (size_t i = 0; i < arg_names.size(); i++) {
+    if (arg_names[i] == "wmode") {
+      // In theory content other than Flash could have a "wmode" argument,
+      // but that's pretty unlikely.
+      if (arg_values[i] == "direct" || arg_values[i] == "gpu")
+        needs_gpu = true;
+      break;
+    }
+  }
+  // 0 : No 3D content and GPU is blacklisted
+  // 1 : No 3D content and GPU is not blacklisted
+  // 2 : 3D content but GPU is blacklisted
+  // 3 : 3D content and GPU is not blacklisted
+  // 4 : No 3D content and GPU is blacklisted on XP
+  // 5 : No 3D content and GPU is not blacklisted on XP
+  // 6 : 3D content but GPU is blacklisted on XP
+  // 7 : 3D content and GPU is not blacklisted on XP
+  UMA_HISTOGRAM_ENUMERATION("Flash.UsesGPU",
+      is_xp * 4 + needs_gpu * 2 + prefs.is_webgl_supported, 8);
+#endif
+}
+
 bool PluginInstance::Initialize(WebPluginContainer* container,
                                 const std::vector<std::string>& arg_names,
                                 const std::vector<std::string>& arg_values,
@@ -544,6 +577,8 @@ bool PluginInstance::Initialize(WebPluginContainer* container,
 
   container_->setIsAcceptingTouchEvents(IsAcceptingTouchEvents());
 
+  SetGPUHistogram(delegate_->GetPreferences(), arg_names, arg_values);
+
   argn_ = arg_names;
   argv_ = arg_values;
   scoped_array<const char*> argn_array(StringVectorToArgArray(argn_));