Use smaller metadata in ServiceWorkerInstalledScriptsSenderTest.FailedToSendMetaData

The test is failing on android-marshmallow-x86-fyi-rel. We suspect
the failure comes from writing large metadata. This CL reduces the
size of metadata to attempt to fix the failure.

Bug: 1081502
Change-Id: I3c8ebac33b1ec757b00aff56e2d8eb9da55b652f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2202825Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769634}

content/browser/service_worker/service_worker_installed_scripts_sender_unittest.cc

@@ -21,6 +21,7 @@
 #include "net/base/io_buffer.h"
 #include "net/base/test_completion_callback.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/blink/public/common/blob/blob_utils.h"
 #include "third_party/blink/public/mojom/service_worker/service_worker_registration.mojom.h"
 
 namespace content {
@@ -300,7 +301,7 @@ TEST_F(ServiceWorkerInstalledScriptsSenderTest, FailedToSendBody) {
 TEST_F(ServiceWorkerInstalledScriptsSenderTest, FailedToSendMetaData) {
   const GURL kMainScriptURL = version()->script_url();
   std::string long_meta_data = "I'm the meta data!";
-  long_meta_data.resize(3E6, '!');
+  long_meta_data.resize(blink::BlobUtils::GetDataPipeCapacity(3E6) + 1, '!');
   std::map<GURL, ExpectedScriptInfo> kExpectedScriptInfoMap = {
       {kMainScriptURL,
        {1,