Fix crash upload test on Android.

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R=ppi@chromium.org

Review URL: https://codereview.chromium.org/1311913009 .

shell/crash/crash_upload_unittests.cc

diff --git a/shell/crash/crash_upload_unittests.cc b/shell/crash/crash_upload_unittests.cc
index ee2750a..f361678 100644
--- a/shell/crash/crash_upload_unittests.cc
+++ b/shell/crash/crash_upload_unittests.cc
@@ -91,7 +91,7 @@
 };
 
 std::string GetDumpContent(const base::FilePath& path) {
-  return "--" + path.value() + "\r\n";
+  return "--" + path.BaseName().value() + "\r\n";
 }
 
 void CreateValidDump(const base::FilePath& path, const base::Time& time) {