Display tcmalloc debug output from renderer processes in about:tcmalloc.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/255080

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28384 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 42 insertions, 0 deletions

diff --git a/chrome/browser/browser_about_handler.h b/chrome/browser/browser_about_handler.h
index 87e5e75..56125ca 100644
--- a/chrome/browser/browser_about_handler.h
+++ b/chrome/browser/browser_about_handler.h
@@ -7,6 +7,13 @@
 #ifndef CHROME_BROWSER_BROWSER_ABOUT_HANDLER_H_
 #define CHROME_BROWSER_BROWSER_ABOUT_HANDLER_H_
 
+#include <map>
+#include <string>
+
+#include "base/process.h"
+#include "base/singleton.h"
+#include "base/string_util.h"
+
 class GURL;
 class Profile;
 
@@ -23,4 +30,39 @@ bool WillHandleBrowserAboutURL(GURL* url, Profile* profile);
 // case, normal tab navigation should be skipped.
 bool HandleNonNavigationAboutURL(const GURL& url);
 
+#if defined(USE_TCMALLOC)
+// A map of header strings (e.g. "Browser", "Renderer PID 123")
+// to the tcmalloc output collected for each process.
+typedef std::map<std::string, std::string> AboutTcmallocOutputsType;
+
+class AboutTcmallocOutputs {
+ public:
+  AboutTcmallocOutputs() {}
+
+  AboutTcmallocOutputsType* outputs() { return &outputs_; }
+
+  // Records the output for a specified header string.
+  void SetOutput(std::string header, std::string output) {
+    outputs_[header] = output;
+  }
+
+  // Callback for output returned from renderer processes.  Adds
+  // the output for a canonical renderer header string that
+  // incorporates the pid.
+  void RendererCallback(base::ProcessId pid, std::string output) {
+    SetOutput(StringPrintf("Renderer PID %d", static_cast<int>(pid)), output);
+  }
+
+ private:
+  AboutTcmallocOutputsType outputs_;
+
+  friend struct DefaultSingletonTraits<AboutTcmallocOutputs>;
+
+  DISALLOW_COPY_AND_ASSIGN(AboutTcmallocOutputs);
+};
+
+// Glue between the callback task and the method in the singleton.
+void AboutTcmallocRendererCallback(base::ProcessId pid, std::string output);
+#endif
+
 #endif  // CHROME_BROWSER_BROWSER_ABOUT_HANDLER_H_