Disable a flaky test ParallelDownloadTest.ParallelDownloadComplete on Android and Linux

Bug: 786626
Change-Id: I8a5a3d5673f7a1fc57bb87791fb93411ae16adf2
Tbr: qinmin@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/778342Reviewed-by: Takeshi Yoshino <tyoshino@chromium.org>
Commit-Queue: Takeshi Yoshino <tyoshino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517780}

content/browser/download/download_browsertest.cc

@@ -2894,7 +2894,13 @@ IN_PROC_BROWSER_TEST_F(DownloadContentTest,
 }
 
 // Verify parallel download in normal case.
-IN_PROC_BROWSER_TEST_F(ParallelDownloadTest, ParallelDownloadComplete) {
+// Flaky. See http://crbug.com/786626.
+#if defined(OS_ANDROID) || defined(OS_LINUX)
+#define MAYBE_ParallelDownloadComplete DISABLED_ParallelDownloadComplete
+#else
+#define MAYBE_ParallelDownloadComplete ParallelDownloadComplete
+#endif
+IN_PROC_BROWSER_TEST_F(ParallelDownloadTest, MAYBE_ParallelDownloadComplete) {
   InitParallelDownloadFeature();
   EXPECT_TRUE(base::FeatureList::IsEnabled(features::kParallelDownloading));