[ios] Fix memory footprint recording for synthetic crash reports

Add BreakpadServerParameterPrefix_ prefix to the key

Bug: 1103752
Change-Id: Ieb4b33d600a57571fb0bbf87326d8c60cc18b800
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533841
Auto-Submit: Eugene But <eugenebut@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826797}

ios/chrome/browser/crash_report/synthetic_crash_report_util.mm

@@ -114,7 +114,7 @@ void CreateSyntheticCrashReportForUte(
                  base::NumberToString(static_cast<long>(uptime * 1000)));
   }
 
-  AppendConfig(config, "memory_footprint",
+  AppendConfig(config, "BreakpadServerParameterPrefix_memory_footprint",
                base::NumberToString(previous_session.memoryFootprint));
 
   // Write empty minidump file, as Breakpad can't upload config without the

ios/chrome/browser/crash_report/synthetic_crash_report_util_unittest.mm

@@ -198,7 +198,7 @@ TEST_F(SyntheticCrashReportUtilTest, CreateSyntheticCrashReportForUte) {
             config_lines[53]);
   EXPECT_EQ(base::NumberToString(kUptimeMs), config_lines[54]);
 
-  EXPECT_EQ("memory_footprint", config_lines[55]);
+  EXPECT_EQ("BreakpadServerParameterPrefix_memory_footprint", config_lines[55]);
   EXPECT_EQ(base::NumberToString(base::NumberToString(kMemoryFootprint).size()),
             config_lines[56]);
   EXPECT_EQ(base::NumberToString(kMemoryFootprint), config_lines[57]);