Switch chrome_elf exception handling from breakpad to crashpad.

chrome/app/chrome_crash_reporter_client_win.cc

Index: chrome/app/chrome_crash_reporter_client_win.cc
diff --git a/chrome/app/chrome_crash_reporter_client_win.cc b/chrome/app/chrome_crash_reporter_client_win.cc
index 42e2093efa73d2506a45a87d0b89b2b4cc974dc0..61197252af72d76c843705eaec3e8a54595f3dc9 100644
--- a/chrome/app/chrome_crash_reporter_client_win.cc
+++ b/chrome/app/chrome_crash_reporter_client_win.cc
@@ -69,6 +69,12 @@ int snprintf(char* buffer,
 }
 
 size_t RegisterCrashKeysHelper() {
+  // Crash keys should be registered only once for the duration of the

[scottmg, 2016/06/27 19:37:46]

Why is this getting called multiple times now?

[ananta, 2016/06/27 20:00:26]

Can get called from child_process_logging_win.cc which is part of this patchset.
Don't want to register keys twice as that fires DCHECK's

+  // process.
+  static size_t registered_keys_size = 0;
+  if (registered_keys_size)
+    return registered_keys_size;
+
   // The following keys may be chunked by the underlying crash logging system,
   // but ultimately constitute a single key-value pair.
   //
@@ -172,7 +178,9 @@ size_t RegisterCrashKeysHelper() {
     }
   }
 
-  return base::debug::InitCrashKeys(&keys[0], keys.size(), kChunkMaxLength);
+  registered_keys_size =
+      base::debug::InitCrashKeys(&keys[0], keys.size(), kChunkMaxLength);
+  return registered_keys_size;
 }
 
 }  // namespace
@@ -201,6 +209,11 @@ void ChromeCrashReporterClient::InitializeCrashReportingForProcess() {
 }
 #endif  // NACL_WIN64
 
+// static
+void ChromeCrashReporterClient::RegisterCrashKeysForDebugging() {
+  RegisterCrashKeysHelper();
+}
+
 bool ChromeCrashReporterClient::GetAlternativeCrashDumpLocation(
     base::string16* crash_dir) {
   // By setting the BREAKPAD_DUMP_LOCATION environment variable, an alternate