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..f835bb43a1431d2d063d7fa67bef61bed4f7ead9 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 +535,33 @@ 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. This only tests
+  // on XP at the moment.
+#if defined(OS_WIN)
+  if (base::win::GetVersion() <= base::win::VERSION_XP) {
+    bool needs_gpu = false;
+
+    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;
+      }
+    }
+    // The value of this histogram is 1 or 3 if 3D is not blacklisted on this
+    // card, and 2 or 3 if the content needs the GPU.

[vangelis, 2012/08/28 17:30:23]

Maybe it would be more clear to enumerate the potential results:
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

Also, since you're in here, should we do this for other versions of windows?  It
would be useful to know where we stand there too.

+    UMA_HISTOGRAM_ENUMERATION("Flash.UsesGPU",
+        needs_gpu * 2 + prefs.is_webgl_supported, 4);
+  }
+#endif
+}
+
 bool PluginInstance::Initialize(WebPluginContainer* container,
                                 const std::vector<std::string>& arg_names,
                                 const std::vector<std::string>& arg_values,
@@ -544,6 +573,8 @@ 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_));