Create the crash key registration system and register some Mac-specific keys.

base/debug/crash_logging.h

Index: base/debug/crash_logging.h
diff --git a/base/debug/crash_logging.h b/base/debug/crash_logging.h
index c39c41d0363a1954e45984d213f8d2930a5c9103..a55da6ff2bfd00b0b1b9076cfd883146aef92c5a 100644
--- a/base/debug/crash_logging.h
+++ b/base/debug/crash_logging.h
@@ -51,6 +51,30 @@ class BASE_EXPORT ScopedCrashKey {
   DISALLOW_COPY_AND_ASSIGN(ScopedCrashKey);
 };
 
+// Before setting values for a key, all the keys must be registered.
+struct BASE_EXPORT CrashKey {
+  // The name of the crash key, used in the above functions.
+  const char* const key_name;
+
+  // For values longer than max_length, the value can be chunked into values
+  // named "key_name-1", "key_name-2", etc. This is the maximum number of
+  // numbered chunks to use before the value is truncated.
+  size_t num_chunks;
+
+  // The maximum length of a single chunk. Truncation happens if the value is
+  // greater than |num_chunks * max_length|.
+  size_t max_length;
+};
+
+// Before the crash key logging mechanism can be used, all crash keys must be
+// registered with this function. The crash reporting implementation should
+// allocate space for exactly |out_key_storage_size| crash keys.
+BASE_EXPORT void InitCrashKeys(const CrashKey* const keys, size_t count,
+                               size_t* out_key_storage_size);

[Scott Hess - ex-Googler, 2013/01/09 22:34:20]

I'm still -1 on having a size_t* out parameter when your return value is void. 
Might as well just return the value, the caller can ignore it.

[Robert Sesek, 2013/01/09 23:06:30]

OK, I don't feel strongly enough to argue ;). Done.

+
+// Returns the correspnding crash key object or NULL for a given key.
+BASE_EXPORT const CrashKey* LookupCrashKey(const base::StringPiece& key);
+
 typedef void (*SetCrashKeyValueFuncT)(const base::StringPiece&,
                                       const base::StringPiece&);
 typedef void (*ClearCrashKeyValueFuncT)(const base::StringPiece&);
@@ -61,6 +85,14 @@ BASE_EXPORT void SetCrashKeyReportingFunctions(
     SetCrashKeyValueFuncT set_key_func,
     ClearCrashKeyValueFuncT clear_key_func);
 
+// Helper function that breaks up a value according to the parameters
+// specified by the crash key object.
+BASE_EXPORT std::vector<std::string> ChunkCrashKeyValue(
+    const CrashKey& crash_key, const base::StringPiece& value);
+
+// Resets the crash key system so it can be reinitialized. For testing only.
+BASE_EXPORT void ResetCrashLoggingForTesting();
+
 }  // namespace debug
 }  // namespace base