Web Share Target for Chrome OS: Skip blank title

If an Intent is received that has a blank title, we don't
include the title in the generated GET or POST request.

Current Intent instances are created with either non-empty
strings or with nullopt. This CL protects against any
future Intent sources that might create share_title
with empty string.

Bug: 1125880
Change-Id: I5b5a854eb8b849d1d07877f46e3855cf29c6109e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2592544
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Alan Cutter <alancutter@chromium.org>
Auto-Submit: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837904}

chrome/browser/ui/web_applications/share_target_utils.cc

@@ -37,7 +37,8 @@ std::vector<SharedField> ExtractSharedFields(
     const apps::mojom::Intent& intent) {
   std::vector<SharedField> result;
 
-  if (!share_target.params.title.empty() && intent.share_title.has_value()) {
+  if (!share_target.params.title.empty() && intent.share_title.has_value() &&
+      !intent.share_title->empty()) {
     result.push_back(
         {.name = share_target.params.title, .value = *intent.share_title});
   }
@@ -125,6 +126,7 @@ NavigateParams NavigateParamsForShareTarget(
   std::vector<SharedField> shared_fields =
       ExtractSharedFields(share_target, intent);
   for (const auto& shared_field : shared_fields) {
+    DCHECK(!shared_field.value.empty());
     names.push_back(shared_field.name);
     values.push_back(shared_field.value);
     filenames.push_back(std::string());

chrome/browser/ui/web_applications/share_target_utils_unittest.cc

@@ -113,4 +113,19 @@ TEST(ShareTargetUtils, ExtractTitleTextUrl) {
   }
 }
 
+TEST(ShareTargetUtils, SkipEmpty) {
+  apps::mojom::Intent intent;
+  intent.share_title = "";
+  intent.share_text = "";
+
+  {
+    apps::ShareTarget share_target;
+    share_target.params.title = "subject";
+    share_target.params.text = "body";
+    share_target.params.url = "link";
+    EXPECT_EQ(ExtractSharedFields(share_target, intent),
+              std::vector<SharedField>());
+  }
+}
+
 }  // namespace web_app

chrome/browser/ui/web_applications/web_share_target_browsertest.cc

@@ -186,6 +186,8 @@ IN_PROC_BROWSER_TEST_F(WebShareTargetBrowserTest, ShareAudio) {
     std::vector<std::string> content_types(3, "audio/webm");
     intent = apps_util::CreateShareIntentFromFiles(
         profile(), std::move(file_paths), std::move(content_types));
+    intent->share_text = "";
+    intent->share_title = "";
   }
 
   content::WebContents* const web_contents =
@@ -195,6 +197,25 @@ IN_PROC_BROWSER_TEST_F(WebShareTargetBrowserTest, ShareAudio) {
   RemoveWebShareDirectory(directory);
 }
 
+IN_PROC_BROWSER_TEST_F(WebShareTargetBrowserTest, PostBlank) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+  const GURL app_url =
+      embedded_test_server()->GetURL("/web_share_target/poster.html");
+  const AppId app_id = web_app::InstallWebAppFromManifest(browser(), app_url);
+
+  apps::mojom::IntentPtr intent = apps_util::CreateShareIntentFromFiles(
+      profile(), /*file_paths=*/std::vector<base::FilePath>(),
+      /*mime_types=*/std::vector<std::string>());
+
+  content::WebContents* const web_contents =
+      LaunchAppWithIntent(app_id, std::move(intent), share_target_url());
+
+  // Poster web app's service worker detects omitted values.
+  EXPECT_EQ("N/A", ReadTextContent(web_contents, "headline"));
+  EXPECT_EQ("N/A", ReadTextContent(web_contents, "author"));
+  EXPECT_EQ("N/A", ReadTextContent(web_contents, "link"));
+}
+
 IN_PROC_BROWSER_TEST_F(WebShareTargetBrowserTest, PostLink) {
   ASSERT_TRUE(embedded_test_server()->Start());
   const GURL app_url =