[ios] Add kDCheckIsFatalFeature feature.

This will be used to enable breakpad uploads for DCHECKs in canary.

Bug: 919094
Change-Id: I8e76db99696e7a948d2d740f0568cba41b1b4dce
Reviewed-on: https://chromium-review.googlesource.com/c/1410992
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622990}

ios/chrome/browser/about_flags.mm

@@ -515,6 +515,11 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
      flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(
          autofill::features::kAutocompleteRetentionPolicyEnabled)},
+#if defined(DCHECK_IS_CONFIGURABLE)
+    {"dcheck-is-fatal", flag_descriptions::kDcheckIsFatalName,
+     flag_descriptions::kDcheckIsFatalDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(base::kDCheckIsFatalFeature)},
+#endif  // defined(DCHECK_IS_CONFIGURABLE)
 };
 
 // Add all switches from experimental flags to |command_line|.

ios/chrome/browser/ios_chrome_flag_descriptions.cc

@@ -55,6 +55,13 @@ const char kCompactTranslateInfobarDescription[] =
     "When enabled, replaces the exisitng translate infobars with a new compact "
     "one.";
 
+#if defined(DCHECK_IS_CONFIGURABLE)
+const char kDcheckIsFatalName[] = "DCHECKs are fatal";
+const char kDcheckIsFatalDescription[] =
+    "By default Chrome will evaluate in this build, but only log failures, "
+    "rather than crashing. If enabled, DCHECKs will crash the calling process.";
+#endif  // defined(DCHECK_IS_CONFIGURABLE)
+
 const char kEnableAutofillCreditCardUploadUpdatePromptExplanationName[] =
     "Enable updated prompt explanation when offering credit card upload";
 const char kEnableAutofillCreditCardUploadUpdatePromptExplanationDescription[] =

ios/chrome/browser/ios_chrome_flag_descriptions.h

@@ -38,6 +38,12 @@ extern const char kBreakpadNoDelayInitialUploadDescription[];
 extern const char kCompactTranslateInfobarName[];
 extern const char kCompactTranslateInfobarDescription[];
 
+#if defined(DCHECK_IS_CONFIGURABLE)
+// Title and description for the flag to enable configurable DCHECKs.
+extern const char kDcheckIsFatalName[];
+extern const char kDcheckIsFatalDescription[];
+#endif  // defined(DCHECK_IS_CONFIGURABLE)
+
 // Title and description for the flag to control if a crash report is generated
 // on main thread freeze.
 extern const char kDetectMainThreadFreezeName[];