re-use WebUIs

chrome/browser/ui/webui/tracing_ui.cc

Index: chrome/browser/ui/webui/tracing_ui.cc
diff --git a/chrome/browser/ui/webui/tracing_ui.cc b/chrome/browser/ui/webui/tracing_ui.cc
index dce1f4ad514580df6236eed9e95ed2259008a8fa..25e33e450c9e9f7eb033ca67e2e8529924acb689 100644
--- a/chrome/browser/ui/webui/tracing_ui.cc
+++ b/chrome/browser/ui/webui/tracing_ui.cc
@@ -117,6 +117,8 @@ class TracingMessageHandler
   // True while system tracing is active.
   bool system_trace_in_progress_;
 

[Dan Beam, 2012/04/21 02:53:07]

doc comment

+  bool observing_;
+
   void OnEndSystemTracingAck(
       const scoped_refptr<base::RefCountedString>& events_str_ptr);
 
@@ -158,7 +160,8 @@ class TaskProxy : public base::RefCountedThreadSafe<TaskProxy> {
 TracingMessageHandler::TracingMessageHandler()
   : select_trace_file_dialog_type_(SelectFileDialog::SELECT_NONE),
     trace_enabled_(false),
-    system_trace_in_progress_(false) {
+    system_trace_in_progress_(false),
+    observing_(true) {

[stuartmorgan, 2012/04/24 09:12:20]

Same issue here.

[Evan Stade, 2012/04/24 17:52:40]

Done.

 }
 
 TracingMessageHandler::~TracingMessageHandler() {
@@ -208,7 +211,9 @@ void TracingMessageHandler::OnTracingControllerInitialized(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   // Watch for changes in GPUInfo
-  GpuDataManager::GetInstance()->AddObserver(this);
+  if (!observing_)
+    GpuDataManager::GetInstance()->AddObserver(this);
+  observing_ = true;
 
   // Tell GpuDataManager it should have full GpuInfo. If the
   // Gpu process has not run yet, this will trigger its launch.