[tracing] Allow enabling heap profiling from chrome://flags

chrome/browser/flag_descriptions.h

Index: chrome/browser/flag_descriptions.h
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index f7b42273228255b264acb89cd6a816ed8019cd3e..4103afb7ca797f0243280628c2cb49d955ea4f87 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -3323,6 +3323,15 @@ extern const char kOmniboxDisplayTitleForCurrentUrlName[];
 // for current URL.
 extern const char kOmniboxDisplayTitleForCurrentUrlDescription[];
 
+// Name & description for the heap profiling flag.
+extern const char kEnableHeapProfilingName[];
+extern const char kEnableHeapProfilingDescription[];
+
+// Descriptions of the different heap profiling modes.
+extern const char kEnableHeapProfilingModePseudo[];
+extern const char kEnableHeapProfilingModeNative[];
+extern const char kEnableHeapProfilingTaskProfiler[];
+
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_