Set a "metrics_client_id" crash key instead of "guid" on Mac OS X

chrome/common/crash_keys.cc

Index: chrome/common/crash_keys.cc
diff --git a/chrome/common/crash_keys.cc b/chrome/common/crash_keys.cc
index 1983f0d73ec93b37ac16d974176d59dfb2611c88..dfe0f425b16928195c6448753c34cd0e7eb1a6c9 100644
--- a/chrome/common/crash_keys.cc
+++ b/chrome/common/crash_keys.cc
@@ -55,7 +55,13 @@ static_assert(kMediumSize <= kSingleChunkLength,
               "mac has medium size crash key chunks");
 #endif
 
+#if defined(OS_MACOSX)
+// Crashpad owns the "guid" key. Chrome's metrics client ID is a separate ID
+// carried in a distinct "metrics_client_id" field.
+const char kMetricsClientId[] = "metrics_client_id";
+#else
 const char kClientId[] = "guid";
+#endif
 
 const char kChannel[] = "channel";
 
@@ -123,7 +129,11 @@ size_t RegisterChromeCrashKeys() {
   // The following keys may be chunked by the underlying crash logging system,
   // but ultimately constitute a single key-value pair.
   base::debug::CrashKey fixed_keys[] = {
+#if defined(OS_MACOSX)
+    { kMetricsClientId, kSmallSize },
+#else
     { kClientId, kSmallSize },
+#endif
     { kChannel, kSmallSize },
     { kActiveURL, kLargeSize },
     { kNumSwitches, kSmallSize },
@@ -234,14 +244,40 @@ size_t RegisterChromeCrashKeys() {
                                     kSingleChunkLength);
 }
 
-void SetCrashClientIdFromGUID(const std::string& client_guid) {
-  std::string stripped_guid(client_guid);
+void SetMetricsClientIdFromGUID(const std::string& metrics_client_guid) {
+  std::string stripped_guid(metrics_client_guid);
   // Remove all instance of '-' char from the GUID. So BCD-WXY becomes BCDWXY.
   ReplaceSubstringsAfterOffset(&stripped_guid, 0, "-", "");
   if (stripped_guid.empty())
     return;
 
+#if defined(OS_MACOSX)
+  // The crash client ID is maintained by Crashpad and is distinct from the
+  // metrics client ID, which is carried in its own key.
+  base::debug::SetCrashKeyValue(kMetricsClientId, stripped_guid);
+#else
+  // The crash client ID is set by the application when Breakpad is in use.
+  // The same ID as the metrics client ID is used.
   base::debug::SetCrashKeyValue(kClientId, stripped_guid);
+#endif
+}
+
+void ClearMetricsClientId() {
+#if defined(OS_MACOSX)
+  // Crashpad always monitors for crashes, but doesn't upload them when
+  // crash reporting is disabled. The preference to upload crash reports is
+  // linked to the preference for metrics reporting. When metrics reporting is
+  // disabled, don't put the metrics client ID into crash dumps. This way, crash
+  // reports that are saved but not uploaded will not have a metrics client ID
+  // from the time that metrics reporting was disabled even if they are uploaded
+  // by user action at a later date.
+  //
+  // Breakpad cannot be enabled or disabled without an application restart, and
+  // it needs to use the metrics client ID as its stable crash client ID, so
+  // leave its client ID intact even when metrics reporting is disabled while
+  // the application is running.
+  base::debug::ClearCrashKey(kMetricsClientId);
+#endif
 }
 
 static bool IsBoringSwitch(const std::string& flag) {
@@ -271,6 +307,11 @@ static bool IsBoringSwitch(const std::string& flag) {
          // (If you need to know can always look at the PEB).
          flag == "--flag-switches-begin" ||
          flag == "--flag-switches-end";
+#elif defined(OS_MACOSX)
+  // These are carried in their own fields.
+  return StartsWithASCII(flag, "--channel=", true) ||
+         StartsWithASCII(flag, "--type=", true) ||
+         StartsWithASCII(flag, "--metrics-client-id=", true);
 #elif defined(OS_CHROMEOS)
   static const char* const kIgnoreSwitches[] = {
     ::switches::kEnableLogging,