[UMA] Use proper C++ objects to serialize tracked_objects across process boundaries.

base/location.h

Index: base/location.h
diff --git a/base/location.h b/base/location.h
index fc9d3603251a27f526f599e564714ec3bb5befbc..ce948d02fed66aaf9c2ca45223ad7451487c9925 100644
--- a/base/location.h
+++ b/base/location.h
@@ -9,10 +9,6 @@
 
 #include "base/base_export.h"
 
-namespace base {
-class DictionaryValue;
-}
-
 namespace tracked_objects {
 
 // Location provides basic info where of an object was constructed, or was
@@ -61,10 +57,6 @@ class BASE_EXPORT Location {
   // Write function_name_ in HTML with '<' and '>' properly encoded.
   void WriteFunctionName(std::string* output) const;
 
-  // Construct a Value* representation.  The caller assumes ownership of the
-  // memory in the returned instance.
-  base::DictionaryValue* ToValue() const;
-
  private:
   const char* function_name_;
   const char* file_name_;
@@ -72,6 +64,19 @@ class BASE_EXPORT Location {
   const void* program_counter_;
 };
 
+// Serialized representation of the Location class that can safely be passed
+// across process boundaries.
+struct BASE_EXPORT SerializedLocation {

[jar (doing other things), 2012/03/21 18:19:55]

IMO: It is much better to use classes, and accessors, than to use a struct. The
privacy of the members makes it easy to read locally, without fears that other
folks will change the interior values.

[Ilya Sherman, 2012/03/21 19:23:02]

Hmm.  If these were to be classes, they would need both setters and getters, as
(to the best of my knowledge) the IPC code requires some way to initialize data
other than through the constructor.  So, making these be proper classes, rather
than structs, would not add any safety, but it would add a bunch of extra
boiler-plate code...

+  // The default constructor is exposed to support the IPC serialization macros.
+  SerializedLocation();
+  explicit SerializedLocation(const tracked_objects::Location& location);
+  ~SerializedLocation();
+
+  std::string file_name;
+  std::string function_name;
+  int line_number;
+};
+
 BASE_EXPORT const void* GetProgramCounter();
 
 // Define a macro to record the current source location.