Remove redundant main frame check in InstallableManager

Found while doing an audit of WebContents::GetMainFrame().
web_contents->GetMainFrame()->GetParent() will always return null.

Change-Id: Idc5d2ed719a400a300198b9c36ab4e3307934556
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2422440
Commit-Queue: Adithya Srinivasan <adithyas@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809320}

chrome/browser/installable/installable_logging.cc

@@ -15,8 +15,6 @@
 namespace {
 
 // Error message strings corresponding to the InstallableStatusCode enum.
-static const char kNotInMainFrameMessage[] =
-    "Page is not loaded in the main frame";
 static const char kNotFromSecureOriginMessage[] =
     "Page is not served from a secure origin";
 static const char kNoManifestMessage[] = "Page has no manifest <link> URL";
@@ -68,7 +66,6 @@ static const char kManifestDisplayOverrideNotSupportedMessage[] =
     "Manifest contains 'display_override' field, and the first supported "
     "display mode must be one of 'standalone', 'fullscreen', or 'minimal-ui'";
 
-static const char kNotInMainFrameId[] = "not-in-main-frame";
 static const char kNotFromSecureOriginId[] = "not-from-secure-origin";
 static const char kNoManifestId[] = "no-manifest";
 static const char kManifestEmptyId[] = "manifest-empty";
@@ -132,9 +129,6 @@ std::string GetErrorMessage(InstallableStatusCode code) {
     case SHOWING_APP_INSTALLATION_DIALOG:
     case MAX_ERROR_CODE:
       break;
-    case NOT_IN_MAIN_FRAME:
-      message = kNotInMainFrameMessage;
-      break;
     case NOT_FROM_SECURE_ORIGIN:
       message = kNotFromSecureOriginMessage;
       break;
@@ -238,9 +232,6 @@ content::InstallabilityError GetInstallabilityError(
     case SHOWING_APP_INSTALLATION_DIALOG:
     case MAX_ERROR_CODE:
       break;
-    case NOT_IN_MAIN_FRAME:
-      error_id = kNotInMainFrameId;
-      break;
     case NOT_FROM_SECURE_ORIGIN:
       error_id = kNotFromSecureOriginId;
       break;

chrome/browser/installable/installable_logging.h

@@ -22,7 +22,7 @@ enum InstallableStatusCode {
   RENDERER_EXITING = 1,
   RENDERER_CANCELLED = 2,
   USER_NAVIGATED = 3,
-  NOT_IN_MAIN_FRAME = 4,
+  // NOT_IN_MAIN_FRAME = 4 (DEPRECATED),
   NOT_FROM_SECURE_ORIGIN = 5,
   NO_MANIFEST = 6,
   MANIFEST_EMPTY = 7,

chrome/browser/installable/installable_manager.cc

@@ -591,9 +591,6 @@ void InstallableManager::CheckEligiblity() {
           ->IsOffTheRecord()) {
     eligibility_->errors.push_back(IN_INCOGNITO);
   }
-  if (web_contents->GetMainFrame()->GetParent()) {
-    eligibility_->errors.push_back(NOT_IN_MAIN_FRAME);
-  }
   if (!IsContentSecure(web_contents)) {
     eligibility_->errors.push_back(NOT_FROM_SECURE_ORIGIN);
   }