Add UMA for --app-shim-error.

chrome/app/app_mode_loader_mac.mm

Index: chrome/app/app_mode_loader_mac.mm
diff --git a/chrome/app/app_mode_loader_mac.mm b/chrome/app/app_mode_loader_mac.mm
index 7a489ebea0ca0b02663cf2e75a989be7a6b9f357..6993ae5c7e1e36b182503f882ba8a8ae56373aae 100644
--- a/chrome/app/app_mode_loader_mac.mm
+++ b/chrome/app/app_mode_loader_mac.mm
@@ -140,6 +140,13 @@ int LoadFrameworkAndStart(app_mode::ChromeAppModeInfo* info) {
             app_mode::kLaunchedAfterRebuild)) {
       command_line.AppendSwitchPath(app_mode::kAppShimError,
                                     app_mode_bundle_path);
+#if defined(ARCH_CPU_32_BITS)

[tapted, 2014/06/26 06:47:05]

I have a hunch this will never be false again on mac.. But I could be wrong

[jackhou1, 2014/06/27 04:55:56]

I don't think it hurts to differentiate this. If it turns out to be useless we
can remove it.

+      command_line.AppendSwitchASCII(app_mode::kAppShimErrorDetail,
+                                     app_mode::kAppShimErrorDetail32Bit);
+#elif defined(ARCH_CPU_64_BITS)
+      command_line.AppendSwitchASCII(app_mode::kAppShimErrorDetail,
+                                     app_mode::kAppShimErrorDetail64Bit);
+#endif
     }
   } else {
     // If the shim was launched directly (instead of by Chrome), first ask